Cadac CDC four User Manual

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CDC FOUR

Digital Mixing Console

User Manual

Cadac Holdings Ltd. One New Street Luton Bedfordshire LU1 5DX

Telephone: +44 (0)1582 404202 Fax: +44 (0)1582 412799

Email: General information: info@cadac-sound.com Service enquiries: service@cadac-sound.com

IMPORTANT SAFETY INFORMATION

CAUTION: These servicing instructions are for use by qualied personnel only. To reduce the risk of electric shock, do not perform any servicing other than that contained in the User Manual unless you are qualied to do so. Refer all servicing to qualied service personnel.

1. Read these instructions.

2. Keep these instructions.

3. Heed all warnings.

4. Follow all instructions.

5. Do not use this apparatus near water. Do not expose this apparatus to dripping

or splashing and ensure that no objects lled with liquids, such as vases, are

placed on this apparatus.

6. Clean only with a dry cloth.

7. Do not block any of the ventilation openings. Install in accordance with the manufacturer’s instructions.

8. Do not install near any heat sources such as radiators, heat registers, stoves,

or other apparatus that produce heat.

9. Only use attachments/accessories specied by the manufacturer.

10. Refer all servicing to qualied service personnel. Servicing is required when the apparatus has been damaged in any way, such as the power-supply cord or plug is damaged, liquid has been spilled or objects have fallen into the apparatus, the apparatus has been exposed to rain or moisture, does not operate normally,

or has been dropped.

11. To completely disconnect mains power from this apparatus, the power supply

cord must be unplugged.

For US and CANADA only:

Do not defeat the safety purpose of the grounding-type plug. A grounding-type plug has two blades and a third grounding prong. The wide blade or the third

prong is provided for your safety. When the provided plug does not t into your outlet, consult an electrician for replacement of the obsolete outlet.

The lightning ash with arrowhead symbol, within an equilateral triangle is

intended to alert the user to the presence of an uninsulated “dangerous voltage”

within the product’s enclosure that may be of sufcient magnitude to constitute a

risk of electric shock to persons.

The exclamation point within an equilateral triangle is intended to alert the user to the presence of important operating and maintenance (servicing) instructions in the literature accompanying the appliance.

Revision 1 2012-13CDC FOUR

GENERAL PRECAUTIONS

• Do not place heavy objects on the control surface, expose it to sharp objects or handle the console in any way that may cause damage, e.g., rough

handling and/or excessive vibration.

• Do not subject the equipment to dirt, dust, heat or vibration during operation

or storage. Never expose the console to rain or moisture in any form. Should

the console become wet, turn it off and disconnect it from the mains without further delay. The console should be given sufcient time to dry out before

recommencing operation.

• When cleaning the console, never use chemicals, abrasive substances or

solvents.

• The console control panel should be cleaned using a soft brush and a dry lint-free cloth. For persistent marks, use a soft cloth and isopropyl alcohol.

Switches and potentiometers do NOT require cleaning or lubrication. For

faders, see below.

• Keep these instructions for future reference. Follow all warnings in this

manual and those printed on the console.

• The console must be connected following the guidance in this manual. Never connect power amplier outputs directly to the console. Connectors and

plugs must never be used for any other purpose than that for which they are intended.

• The console mains input must always be connected to correctly rated mains power as referred to in this manual. The mains input must, at all times, be

connected to the local mains power supply using the supplied power cord.

In cases where the supplied plug does not t, a qualied electrician must be

consulted.

• The power cord must be routed in such a way that the risks of accidentally stepping on it, stretching it or it being pinched are minimized.

• WARNING ! THIS EQUIPMENT MUST BE EARTHED !

• Ventilation slots must never be covered or obstructed in any way, otherwise airow required for safe operation may be restricted. Where the console is to be operated in its ight-case, then this must be located in such a way that it

allows for proper ventilation.

• Refer servicing to qualied technical personnel only.

Revision 1 2012-13 CDC FOUR

CONFORMITIES

Declaration of Conformity

The Directives covered by this declaration: 2004/108/EC

The Products Covered by this Declaration: CDC FOUR audio mixing consoles

The Basis on which Conformity is being Declared: The products identied above

comply with the requirements of the above EU Directive(s) by meeting the following standards:

BS EN 55103-1:2009 Product family standard for: audio, video, audio-

visual and entertainment lighting control apparatus for professional use. Part 1 – Emission.

BS EN 55103-2:2009 Product family standard for: audio, video, audio-

visual and entertainment lighting control apparatus for professional use. Part 2 – Immunity.

BS EN 61000-3 -2:2008 Electromagnetic Compatibility (EMC) Part 3. Limits. Section 2. Limits for harmonic current emissions (equipment input

current ≤16 A per phase).

BS EN 61000-3 -3:2006 + A2:2009 Electromagnetic Compatibility (EMC)

Part 3. Limits. Section 3. Limitation of voltage uctuations and icker in low voltage supply systems for equipment with rated current ≤16 A.

BS EN 60065:2002 + A1:2006 Audio, Video and similar electronic apparatus.

Safety requirements.

BS EN 61000-4-2:2009 Electrostatic discharge immunity test.

BS EN 61000-4-6:2009 Immunity to conducted disturbances.

BS EN 61000-4-11:2004 Immunity to voltage dips, short interruptions and

voltage variations

Attention!

The attention of the specier, purchaser, installer, or user is drawn to

special measures and limitations to use which must be observed when these products are taken into service to maintain compliance with the above directives. Details of these special measures and limitations to use

are available on request, and are also contained in this User Manual.

Revision 1 2012-13CDC FOUR

Contents

IMPORTANT SAFETY INFORMATION 3

For US and CANADA only: 3 GENERAL PRECAUTIONS 4 CONFORMITIES 5 Declaration of Conformity 5

Introduction 8

What’s in the Box 8 Overview 8 CDC FOUR – Main Feature Set 9 Stagebox options 10 Mechanical details 11 Power supply matters 12

Controls and Connections 13

Top view - control surface 13 Rear view – connector panel 14 Connector details 15

Block Diagram 18

Fundamentals 19

Central Assignment Module 19 Layers 23 Screen displays - overview 25 Screen navigation 29 Softkeys 30

Audio channel descriptions 31

Input channel 31 Stereo inputs 38 Groups 39 VCA groups 41 Aux outputs 43 Stereo master 45 FX sends and returns 49

Other screen pages 51

Channel 51 Routing 51 Metering 53 EQ detail 54 Dynamics detail 54 FX processing 58 System 62 Scene Control 67

Revision 1 2012-13 CDC FOUR

Other mixer functions 70

Graphic Equaliser 70 USB port 71 Ethernet port 71 MIDI 71 User buttons (U1 – U4) 72

Technical Specication 73

Appendix 74

Input Channel Block Diagram 74 Stereo Inputs block diagram 75 Groups block diagram 76 Aux outputs block diagram 77 Stereo master block diagram 78 Phones/Monitor block diagram 79 Maintenance page 80 Connecting the CDC FOUR to unbalanced sources and destinations 82

Revision 1 2012-13CDC FOUR

Introduction

What’s in the Box

The CDC FOUR console is shipped in a triwall carton. Before unpacking, inspect

that the carton has not been damaged during shipping. If there are any signs of

damage, inform the shipping agent.

Inside the carton, you should nd the following items. If any are missing, contact your Cadac distributor immediately.

• CDC FOUR mixing console

• IEC power cable (with UK/European or US connector as appropriate)

• Detachable gooseneck console lamp

• This manual

Overview

Thank you for purchasing this Cadac CDC FOUR digital audio mixing console.

From its founding in 1967, Cadac’s products have indisputably become the benchmark for sound reinforcement consoles. The CDC FOUR is Cadac’s rst compact digital mixer and is an all new development, based on a proprietary DSP

mix platform. It makes available many of the features of our world-famous large-

scale theatre and touring analogue desks in a compact, portable and fully-digital package. However, you will still nd the attention to detail, high quality audio

circuitry and reliability on which the reputation of the Cadac brand is built.

The CDC FOUR’s basic conguration is 32/4/2, with 16 mic/line mono channels

and 8 stereo channels. It also has 8 aux sends and 8 VCA groups. Input channels can be increased for live work with the optional CDC RACK Stagebox giving up to a further 32 inputs.

Ergonomically, the CDC FOUR employs the now-familiar concept of “layering” to reduce the width of the mixer to less than 19”, having 16 motorised plus one

manual (stereo master) 100 mm faders. The control surface has been designed to be as familiar as possible to operators mainly used to working with analogue

Revision 1 2012-13 CDC FOUR

consoles. All the functions of the single, assignable, largely-standard channel strip are duplicated on the high-resolution TFT colour display, allowing the engineer to

use either “conventional” controls or operate the mixer mainly through the display.

The CDC FOUR has a rear panel expansion port which can be tted with a

dedicated CADAC multichannel digital interface for use with the optional CDC RACK stagebox.

CDC FOUR – Main Feature Set

• 16 mic/line inputs

• 8 stereo inputs

• 4 group outputs plus stereo main output

• 8 VCA groups

• 8 aux sends

• 2 internal FX processors

• 4-band parametric EQ on all channels and groups

• Variable-frequency HPF on all channels

• Dynamics section (compressor/limiter plus gate) on all channels

• Adjustable per-channel delay

• Inserts and Direct Outs on all channels

• Fully-featured Monitor, PFL and Talkback sections

• Internal Universal PSU

• 7” 800 x 480 pixel TFT display

• Scene automation, with 100 mm motorised faders

• 96 kHz, 24-bit Delta-Sigma AD and DA convertors

• Fourth generation 32/40-bit oating-point SHARC processors

• Low-noise, wide dynamic-range analogue mic pre-amps with gain controls

• Channel functions controllable either from standard channel strip or via

display

• Dedicated hardware bargraph meters on each input and stereo main output

• Global metering display

• Dynamics gain reduction displays

• Optional interface card for the CDC RACK expansion stagebox

• Optional remote stageboxes (32-in/16-out or 32-in/8-out) with proprietary

interface

• Optional rackmount kit

• Gooseneck console lamp

• No fans – silent in operation

Revision 1 2012-13CDC FOUR

Stagebox options

The CDC FOUR is designed to integrate immediately with existing analogue live

sound installations, and may be used stand-alone, with a conventional stagebox

and snake.

If more than 16 mic/line channels are required, a CDC-RACK can be added. This is a remote stagebox with integral, remotely-controllable analogue mic pre-amps

of the same high-quality design as those in the CDC FOUR. It uses a proprietary

multichannel digital protocol developed by CADAC to connect to the mixer, and

two coaxial cables replace a conventional snake.

The CDC-RACK is a 19” rack-mounting unit which can be tted with either 16 inputs and 8 outputs, or 32 inputs and 16 outputs. The additional input channels

are available to the user using control surface layers (see ”Layers” on page

23). In the case of the 8-output version, the stagebox output connectors can

be assigned to any eight of the CDC FOUR’s various outputs.

Revision 1 2012-13 CDC FOUR

180.8

9.2

Mechanical details

436.0

569.6

85.5

520.0

NOTE: when installing the CDC FOUR in a permanent or semi-permanent

situation, an additional allowance must be made at the rear of the console for

connectors and cables.

Fitting the rack mounting kit

The CDC FOUR is supplied with a pair of rack mounting brackets which permit the mixer to be installed in a standard 19” equipment rack.

To install the brackets, remove the three upper screws (those closest to the mixer

control surface) which secure each metal end cheek to the chassis. Fit the rack

mounting brackets over the end cheeks and ret the three screws. Note that the brackets are handed (i.e., one is designed to t on the left hand side of the console and the other to the right). This is indicated by an ‘L’ or ‘R’ label afxed

to the bracket.

Revision 1 2012-13CDC FOUR

Power supply matters

The CDC FOUR has an internal Power Supply Unit (PSU). The AC mains power

switch is located on the rear panel, integral with the IEC receptacle to which AC

mains is connected.

Removing the IEC cable from the rear receptacle will electrically isolate the CDC FOUR from the AC mains supply.

It is always good operating practice to turn a mixer on BEFORE turning on the

ampliers, etc., to which its outputs are connected. Similarly, always turn the ampliers off BEFORE turning the mixer OFF.

An IEC cable is supplied with the mixer to connect this to the AC mains supply.

The cable should be tted with a mains plug suitable for your country; if this is not the case, either obtain one of the appropriate type, or replace the tted plug with

one of the correct type. Note the supply mains cable colour coding is as follows:

Mains connection Mains cable core colour

Live Brown

Neutral Blue

Earth (Ground) Green/Yellow

The PSU in the CDC FOUR is a “Universal” type, and may be connected to any

AC mains supply voltage of between 90 and 260 V, and frequency 50 or 60 Hz.

The IEC receptacle is integrated with both the mixer’s power on/off switch and a mains fuseholder (immediately above the connector). If it is necessary to replace

this fuse, please only do so with one of the same type and rating:

115 or 230 V AC

Fuse type T2LA, 20 mm dia. anti-surge

Fuse Rating 2 A

Note that the integral fuseholder has storage space for a spare fuse.

This fuse is the only user-replaceable component the CDC FOUR contains. A

mains fuse should never be replaced without rst making an attempt to ascertain the reason for its failure. If you are unsure why the fuse failed, or if the replacement fuse also fails immediately, consult your Cadac dealer.

Revision 1 2012-13 CDC FOUR

Controls and Connections

Top view - control surface

MIC 1MIC 2 MIC 3MIC 4 MIC 5MIC 6 MIC 7MIC 8 MIC 9MIC 10MIC 11MIC 12MIC 13MIC 14MIC 15MIC 16

60 0600 60 0600 60 0600 60 0600 60 0600 60 0600 60 0600 60 0600 60 0

SOLO

MUTE

VCA 3 AUX 7

SEL

SOLO

MUTE

∞

VCA 4 AUX 8

CHNS 17 - 32

SOLO

MUTE

ST RT 2

AUX 3

CHNS

DEL RCL SVE COPY PASTE

33 - 48

SEL

SOLO

MUTE

∞

TAPE RT

AUX 4

CENTRAL ASSIGNMENT MODULE CENTRAL CONTROL MODULE STEREO MASTER OUTPUT MODULE

TRIM

HPF

GATE

THR

COMP

THR

20:11:1

RAT

LVL

LIM

THR

DLY

SmS

BYP PST

HI LO

48V

FREQ

REV

HPF

HI LO

FREQ

HMF

HI LO

FREQ

LMF

AUT

VIN

HI LO

FREQ

dB dB

SEL

SOLO

MUTE

∞

ST 1

ST 2

GP 1

GP 2

AUX 1

FX 1

∞

PRE

AUX 2

FX 2

∞

PRE

AUX 3

∞

PRE

AUX 4

∞

PRE

AUX 5

∞

EQ IN

SEL

SOLO

MUTE

ST 3 GP 3

LRGR

PRE

AUX 6

∞

PRE

AUX 7

∞

PAN

PRE

AUX 8

∞

PRE

SEL

SOLO

MUTE

∞

ST 4 GP 4

∞

PRE

∞

PRE

LIM

LAYER SELECTCONTROL

SOLO

MUTE

SEL

SOLO

MUTE

50 60

∞

ST 5

ST RT 1

AUX 1

AUX 2

USB

METERS

SCENE

ROUTE

SYSTEM

CHN

CHNS 1 - 16

OUTPUTS

CHNS VCA

50 60

∞

SEL

SOLO

MUTE

CH 9CH 1 CH 2 CH 3 CH 4 CH 5 CH 6 CH 7 CH 8 CH 10 CH11 CH 12 CH 13 CH 14 CH 15 CH 16 MASTER

CH 25CH 17 CH 18 CH 19 CH 20 CH 21 CH 22 CH 23 CH 24 CH 26 CH27 CH 28 CH 29 CH 30 CH 31 CH 32

CH 41CH 33 CH 34 CH 35 CH 36 CH 37 CH 38 CH 39 CH 40 CH 42 CH43 CH 44 CH 45 CH 46 CH 47 CH 48

∞

VCA 1

VCA 2

AUX 5

AUX 6

SOLO LOGIC

ENTERCLEAR

SEL

SOLO

MUTE

50 60

∞

VCA 5

FX 1

HOLD SIP

SEL

SOLO

MUTE

VCA 6

FX 2

TALK

ADJUST

∞

LRGR

COMP

THR

20:1 1:1

RAT

LVL

LIM

THR

BYP

GRAPHIC EQ

1-16

BANDS

17-32

SEL

SOLO

MUTE

50 60

∞

VCA 7 VCA 8

LIM

AUT

VIN

PST

6/12

SEL

SOLO

MUTE MUTE

FREQ

HMF

FREQ

LMF

FREQ

50 60

∞

MONITOR

SUM M

HI LO

TALK BACK

PHONES

SOLO

EQ IN

50 60

∞

Mic pre-amp gain controls

Per-input bargraphs

Central Assignment Module – “channel strip”

Channel faders with SEL, MUTE and SOLO

Stereo fader with MUTE and SOLO

Central Control Module, including TFT screen and primary display controls

Layer selection controls

Screen navigation controls

System utility controls, PTT button and parameter “soft knob”

Stereo output channel

Solo logic controls

Talkback and monitor controls

Graphic equaliser controls

Revision 1 2012-13CDC FOUR

Rear view – connector panel

7 101156

LITTLITES

LEFTRIGHT

MONO

MON M

GP4

AUX 4

AUX 8

TALKBACK

GP3 GP2 GP1

AUX 3AUX 2AUX 1

AUX 7

AUX 6

MON LMON R

TAPE L OUTTAPE R OUT

CH 15

INSDO

AUX 5

INSDO

ST R8 ST L7ST R7 ST L6ST R6 ST L5ST R5 ST L4ST R4 ST L3ST R3 ST L2ST R2 ST L1ST R1

CH 13 CH 11 CH 9 CH 7 CH 5 CH 3CH 1

INSDO

ST L8

INSDO

IN OUT

MIDI

THRU

INSDO

812 13 1415 9

* shown without optional CDC RACK interface installed

No. Connection Qty. Marking

1 Mic/line inputs 16 CH 1-16

2 Stereo line inputs 16 ST 1-8

3 Channel direct outputs (one only indicated) 16 DO

INSDO

ETHERNET

INSDO

CH 2CH 4CH 6CH 8CH 10CH 12CH 14CH 16

INSDO

4 Channel insert send/returns (only one indicated) 16 INS

5 Group outputs 4 GP 1-4

6 Aux send outputs 8 AUX 1-8

7 Stereo master outputs: L, R and mono sum 3 LEFT, RIGHT, MONO

8 Stereo tape outputs 2 TAPE OUT, L & R

9 Monitor outputs: L, R and mono sum 3 MON L, R, M

10 Talkback mic input 1 TALKBACK

11 DC output for console lamp 1 LAMP 12V

12 Expansion port* 1 -

MIDI ports 3 MIDI IN, THRU, OUT

14 Ethernet network port 1 ETHERNET

IEC mains connector, fuse and AC power switch 1 -

* shown without optional CDC RACK interface installed

Revision 1 2012-13 CDC FOUR

Connector details

This section provides electrical details of the CDC FOUR’s inputs and outputs.

The tables at the end of this section, referred to in each connector description,

summarise wiring details.

1. Mic/line inputs 1-16 - Neutrik® Combo A connectors. These sockets accept

either a 3-pin XLR male connector or a ¼” (6.35 mm) 3-pole (TRS) jack plug. The

sensitivity of the XLR input is suitable for microphones, while the jack input, which has an 18 dB pad, is intended for line level sources. The inputs are electronically

balanced with an impedance of 1.2k ohms (mic) or 10k ohms (line). Nominal input

level at the XLR (with gain control at minimum) is 0 dBu; maximum input level is +21 dBu. (Note that Cadac dene 0 dBFS to be equivalent to +21 dBu in the CDC FOUR). 48 V phantom power is available at the XLR pins of this connector,

switchable from the channel strip.

The mic/line inputs should be wired as per Table A (XLR connectors) or as per Table B (jack plugs).

2. Stereo line inputs 1-8 – eight pairs of ¼” (6.35 mm) 3-pole (TRS) jack sockets

(separate L and R inputs). Intended for connection to the line outputs of external

stereo equipment, including outboard FX processors and stereo tape returns.

The inputs are electronically balanced with an impedance of 10k ohms. Nominal

input level is 0 dBu; maximum input level is +21 dBu.

The stereo line inputs should be wired as per Table B.

3. Direct outputs 1-16 – pre-fade outputs from each of the 16 mono mic/line

channels. The outputs are electronically balanced on ¼” (6.35 mm) 3-pole (TRS)

jack sockets, and have a maximum output level of +21 dBu.

The direct outs should be wired as per Table B.

4. Channel inserts 1-16 – send and return insert points in each mono mic/line

channel. The send and return are both unbalanced, and have a maximum level of

+10 dBu. The connectors are ¼” (6.35 mm) 3-pole (TRS) jack sockets.

The inserts should be wired as per Table C.

5. Group outputs 1-4 – post-fade outputs of the four audio subgroups. Outputs

are electronically balanced on ¼” (6.35 mm) 3-pole (TRS) jack sockets, and have

a maximum output level of +21 dBu.

The group outputs should be wired as per Table B.

6. Aux sends 1-8 – the outputs of the mixer’s eight auxiliary busses. Every

channel can send pre- or post-fade to each Aux buss, and each Aux buss has a

master level. The Aux busses can be used as sends to external FX equipment

(normally pre-fade), or as performers’ foldback (normally post-fade). The outputs are electronically balanced on ¼” (6.35 mm) 3-pole (TRS) jack sockets, and have

a maximum output level of +21 dBu.

The Aux sends should be wired as per Table B.

Revision 1 2012-13CDC FOUR

7. Master outputs – the main outputs of the mixer. Three XLR male connectors

are provided: for left and right channels, and a mono sum of left and right (L+R) - 6dB. The outputs are electronically balanced, and have a maximum

output level of +21 dBu.

The master outputs should be wired as per Table A.

8. Tape outputs – a secondary, buffered set of master outputs on ¼” (6.35 mm)

3-pole (TRS) jack sockets, intended to facilitate connection of a stereo recording

device. The signals at the L/R Tape Out connectors are identical to those at the

L/R Master Outputs [7] above, and are post the master fader and mute. There is no equivalent mono sum output. The outputs are electronically balanced, and

have a maximum output level of +21 dBu.

The Tape outputs should be wired as per Table B.

9. Monitor outputs - the mixer’s monitor outputs. Three ¼” (6.35 mm) 3-pole

(TRS) jack sockets provide stereo monitoring, or a mono sum of left and right. The stereo outputs are useful in a recording situation, but the same signal is

available for use in live sound at a dedicated headphone output under the front

armrest, with a separate level control. The mono sum output can also be used

in live sound situations to feed an engineer’s local wedge monitor. The monitor

source may be selected to be the master outputs, the PFL/AFL system or the stereo tape return. The rear panel outputs are electronically balanced, and have

a maximum output level of +21 dBu.

The monitor outputs should be wired as per Table B.

10. Talkback mic – a 3-pin female XLR connector on the rear panel for a

dedicated dynamic mic or connection to a comms system.

The talkback mic should be wired as per Table A.

11. Console lamp – a 3-pin female XLR for connection of a gooseneck lamp to

provide console illumination.

12. Expansion port – this may be tted with an interface card for the CDC RACK

expansion stagebox; this uses a dedicated CADAC digital multichannel protcol.

13. MIDI ports – standard MIDI In, Out and Thru connectors

14. Ethernet port – RJ45 connector for software updates

15. AC mains - see “Power supply matters” on page 12 for wiring details.

Revision 1 2012-13 CDC FOUR

Table A*

Pin Connection

1 Screen

2 Signal ‘hot’ (phase)

3 Signal ‘cold’ (antiphase)

Table B*

Pin Connection

Tip Signal ‘hot’ (phase)

Ring Signal ‘cold’ (antiphase)

Sleeve Screen

Table C

Pin Connection

Tip Send

Ring Return

Sleeve Screen (common)

* See the Appendix for information about connecting the CDC-FOUR to unbalanced sources and destinations.

Revision 1 2012-13CDC FOUR

Block Diagram

STEREO LR

AUX 1-8

FX 1&2

GROUP 1-4

AFL LR

PFL

Aux Output (TRS)

Group Output (TRS)

Monitor Output Left (TRS)

Headphone Output (TRS)

Monitor Output Right (TRS)

Monitor Output Mono (TRS)

Monitor Outputs

Stereo Output Right (XLR)

Mono Output (XLR)

Stereo Output Left (XLR)

Tape Output Left (TRS)

Tape Output Right (TRS)

Stereo Outputs

Internal mix busses

CDC FOUR - Basic Block Diagram

Mono Inputs 1-16 Aux Outputs 1-8

Mono Input (XLR)

Direct Output (TRS)

Insert Send/Return (TRS)

Stereo Inputs 1-8 Group Outputs 1-4

Stereo Input Left (TRS)

Stereo Input Right (TRS)

Internal FX Returns 1 & 2

FX Returns 1 & 2 (Internal)

Revision 1 2012-13 CDC FOUR

Fundamentals

Although the CDC FOUR control surface and operating system has been

designed to retain the familiarity and facilities of an analogue console, there are a

number of important aspects of its operation which differ markedly from analogue mixers. These include the following concepts:

• Assignability - a single channel strip whose controls can be assigned to any of the internal signal channels;

• Layers – the faders can be switched to control another set of channels or groups, resulting in a small control surface for a large conguration mixer;

• TFT screen – most of the mixer’s controls and statuses are accessible through the built-in display as well as by using hardware controls; some mixer functions are only available via the screen;

• Soft keys – various controls whose functions vary depending on the current state of the display, or of other mixer settings.

Central Assignment Module

CENTRAL ASSIGNMENT MODULE

48V

TRIM

REV

HPF

GATE

THR

COMP

THR

20:11:1

AUT

RAT

VIN

LVL

LIM

THR

DLY

SmS

BYP PST

HI LO

FREQ

HI LO

FREQ

HMF

HI LO

FREQ

LMF

HI LO

FREQ

AUX 1

AUX 2

AUX 3

AUX 4

AUX 5

AUX 6

AUX 7

AUX 8

FX 1

∞

PRE

∞

PRE

∞

PRE

∞

PRE

∞

PRE

∞

PRE

∞

PRE

∞

PRE

FX 2

LRGR

PAN

∞

PRE

∞

PRE

SOLO

MUTE

The Central Assignment Module (CAM) is essentially a single,

fully-featured channel strip, such as would be found on an

analogue mixer. The obvious differences are that potentiometers

are replaced by continuous (360°) rotary encoders, and the push-

buttons are electronically latching and internally illuminated. The

encoders have a “press” function; turning the encoder knob while

pressing it in allows a ner degree of parameter adjustment. The

use of rotary encoders means that the value of the parameter

which the control varies is not related to the physical position

of the knob – in fact, the knobs do not have a pointer of any

LIM

kind. Another implication of this system is that all the channel parameters have default values which have nothing to do with

knob positions; these values can be regarded collectively as the

“initial state” of the channel. The actual value of each parameter

is available from the TFT display; this topic is covered in greater

detail under “Screen displays”, see page 25.

The CAM controls the mixer’s DSP section, and is used to set the

channel parameters for the following mixer sections:

• All mono mic/line channels

• Stereo inputs 1-8

• Subgroups 1-4

• Aux. sends 1-8

• FX returns 1 and 2Note that unlike an analogue mixer, many of the channel

facilities found on an input channel strip are available to the output sections

of the CDC FOUR. Furthermore, there is no signicant difference in the

facilities available to stereo line input channels compared to mono mic/line input channels.

However, it should be noted that not every channel facility is available to all types of signal channel. The exceptions are noted in a later section of the manual, see

“Audio channel descriptions” on page 31.

Revision 1 2012-13CDC FOUR

SEL

SOLO

MUTE

CH 1 CH 17 CH 33

TRIM

HPF

GATE

THR

COMP

THR

20:11:1

RAT

LVL

LIM

THR

DLY

SmS

BYP PST

The SEL button

Each fader (except the stereo master) has a SEL button in addition to the usual MUTE and SOLO. The channel for which the CAM is active is selected by pressing SEL. Only one SEL button can be selected at a time. Thus, if the SEL button above Fader 5 is pressed, the CAM will adjust the

parameters of whatever signal is currently assigned to that fader. (Note that each

fader, and hence each SEL button, may be assigned to one of up to ve possible

signals within the mixer. This concept is discussed further under “Layers”, see

page 23.)

The controls on the CAM are now discussed in more detail:

Input stage:

48V

REV

HPF

TRIM - input gain trim.

48v – phantom power at the mic input.

REV – phase reverse.

HPF – variable-frequency high-pass lter.

HPF – high-pass lter frequency.

Dynamics section:

GATE: THR – noise gate threshold.

GATE: IN – noise gate in/out.

AUT

VIN

COMP: THR – compressor threshold.

COMP: RAT – compressor ratio.

COMP: LVL – compressor gain make-up.

COMP: IN – compressor in/out.

COMP: AUT – sets compressor attack/release times automatically

COMP: VIN – selects “vintage” compressor algorithm.

LIM: THR – limiter threshold.

LIM: IN – limiter in/out.

BYP – dynamics section in/out.

PST – dynamics section post-EQ.

DLY

SmS

Delay section:

DLY – delay time.

DLY: IN – delay in/out.

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HI LO

FREQ

HI LO

FREQ

HMF

HI LO

FREQ

LMF

HI LO

FREQ

EQ Section:

HF: IN – HF EQ in/out.

HF: FREQ – EF EQ frequency.

HF: GAIN – HF EQ cut/boost.

HF: Q – HF EQ Q setting.

HF Shelf – HF EQ bell/shelf switch.

HMF: IN – HMF EQ in/out.

HMF: FREQ – HMF EQ frequency.

HMF: GAIN – HMF EQ cut/boost.

HMF: Q – HMF EQ Q setting.

LMF: IN – LMF EQ in/out.

LMF: FREQ – LMF EQ frequency.

LMF: GAIN – LMF EQ cut/boost.

LMF: Q – LMF EQ Q setting.

LF: IN – LF EQ in/out.

LF: FREQ – LF EQ frequency.

LF: GAIN – LF EQ cut/boost.

AUX 1

AUX 2

AUX 3

AUX 4

AUX 5

AUX 6

AUX 7

AUX 8

LF: Q – LF EQ Q setting.

LF Shelf – LF EQ bell/shelf switch.

EQ IN – EQ section in/out.

∞

PRE

∞

PRE

∞

PRE

∞

PRE

∞

PRE

Aux Sends:

AUX 1 – Aux. 1 send level.

AUX 1: ON – Aux. 1 on/off.

AUX 1: PRE – Aux. 1 pre/post.

AUX 2 – Aux. 2 send level.

AUX 2: ON – Aux. 2 on/off.

AUX 2: PRE – Aux. 2 pre/post.

AUX 3 – Aux. 3 send level.

AUX 3: ON – Aux. 3 on/off.

AUX 3: PRE – Aux. 3 pre/post.

∞

PRE

∞

PRE

∞

PRE

AUX 4 – Aux. 4 send level.

AUX 4: ON – Aux. 4 on/off.

AUX 4: PRE – Aux. 4 pre/post.

AUX 5 – Aux. 5 send level.

AUX 5: ON – Aux. 5 on/off.

AUX 5: PRE – Aux. 5 pre/post.

AUX 6 – Aux. 6 send level.

AUX 6: ON – Aux. 6 on/off.

Revision 1 2012-13CDC FOUR

AUX 6: PRE – Aux. 6 pre/post.

AUX 7 – Aux. 7 send level.

AUX 7: ON – Aux. 7 on/off.

AUX 7: PRE – Aux. 7 pre/post.

AUX 8 – Aux. 8 send level.

AUX 8: ON – Aux. 8 on/off.

AUX 8: PRE – Aux. 8 pre/post.

FX 1

∞

PRE

FX 2

∞

PRE

LRGR

PAN

LIM

Internal FX Sends:

FX 1 – FX buss 1 send level.

FX 1: ON – FX 1 on/off.

FX 1: PRE – FX 1 pre/post.

FX 2 – FX buss 2 send level.

FX 2: ON – FX 2 on/off.

FX 2: PRE – FX 2 pre/post.

Routing and metering section:

1 – Group 1 routing button.

2 – Group 2 routing button.

3 – Group 3 routing button.

4 – Group 4 routing button.

L – stereo buss (left) routing button.

R – stereo buss (right) routing button.

PAN – channel pan control.

PAN: IN – Group panning in/out.

L METER – channel bargraph meter (left).

R METER – channel bargraph meter (right).

GR METER – dynamics section gain reduction bargraph meter.

GT – noise gate active LED.

LIM – limiter active LED.

SOLO

Mute and Solo:

SOLO – channel PFL/AFL/SIP solo button.

MUTE

Revision 1 2012-13 CDC FOUR

MUTE – channel mute button.

Layers

On an analogue mixer, the necessity for every channel (input or output) to have

its own set of controls and electronic hardware inevitably means that the physical

size of the mixer becomes proportional to the number of channels. An analogue

mixer with many inputs and outputs has a very large “footprint”.

This relationship may be dispensed with in a digital mixer, which allows a small control surface to control large mixer congurations.

On the CDC FOUR, in 19” of control surface width, sixteen faders can control up to 48 mic/line and 8 stereo inputs, plus eight Aux sends, eight VCA masters,

two internal FX returns and four output groups. This is achieved by arranging all

these various fader-controlled channels into ve* layers. Only one layer at a time is active; the faders, with their associated MUTE, SOLO and SEL buttons control

the sixteen channels in that layer.

NOTE: The red MASTER fader always controls the main stereo output – it is not part of any layer.

LAYER SELECT

CHNS 1 - 16

CHNS

VCA

The active layer is selected by the ve LAYER SELECT buttons ([7] on “Top view

CHNS

33 - 48

17 - 32

OUTPUTS

- control surface” on page 13).

The rst three layers make mic/line inputs 1-16, 17-32 and 33-48 respectively

available to the fader set. The layers corresponding to mic/line inputs 17 and above will only be operative if the CDC RACK stagebox is connected to the mixer. The fader assignments for the mic/line input layers are printed on the fader panel above the faders.

The remaining two layers assign a combination of stereo inputs, VCA masters, group outputs, Aux sends and FX masters to the fader set. The fader assignments

for these layers are printed on the fader panel below the faders.

* The faders may also be assigned to control the 1/3-octave graphic equaliser available to the main

stereo output; this effectively consitutes two additional layers.

Revision 1 2012-13CDC FOUR

The table below summarises the signal which each fader controls in each layer:

LAYER SELECT BUTTON

FADER CHNS 1-16 CHNS 17-24 CHNS 33-48 ST CHNS VCA OUTPUTS

1 Mic/line input 1 Mic/line input 17 Mic/line input 33 Stereo input 1 Output group 1

2 Mic/line input 2 Mic/line input 18 Mic/line input 34 Stereo input 2 Output group 2

3 Mic/line input 3 Mic/line input 19 Mic/line input 35 Stereo input 3 Output group 3

4 Mic/line input 4 Mic/line input 20 Mic/line input 36 Stereo input 4 Output group 4

5 Mic/line input 5 Mic/line input 21 Mic/line input 37 Stereo input 5 Aux Send Master 1

6 Mic/line input 6 Mic/line input 22 Mic/line input 38 Stereo return 1 Aux Send Master 2

7 Mic/line input 7 Mic/line input 23 Mic/line input 39 Stereo return 2 Aux Send Master 3

8 Mic/line input 8 Mic/line input 24 Mic/line input 40 Tape return Aux Send Master 4

9 Mic/line input 9 Mic/line input 25 Mic/line input 41 VCA master 1 Aux Send Master 5

10 Mic/line input 10 Mic/line input 26 Mic/line input 42 VCA master 2 Aux Send Master 6

11 Mic/line input 11 Mic/line input 27 Mic/line input 43 VCA master 3 Aux Send Master 7

12 Mic/line input 12 Mic/line input 28 Mic/line input 44 VCA master 4 Aux Send Master 8

13 Mic/line input 13 Mic/line input 29 Mic/line input 45 VCA master 5 FX Master 1

14 Mic/line input 14 Mic/line input 30 Mic/line input 46 VCA master 6 FX Master 2

15 Mic/line input 15 Mic/line input 31 Mic/line input 47 VCA master 7 -

16 Mic/line input 16 Mic/line input 32 Mic/line input 48 VCA master 8 -

The SEL button for each fader - and hence the entire Central Assignment Module – follows the currently selected layer. Thus pressing the SEL button above Fader

5 will assign the CAM to mic/line input 5 when the layer CHNS 1-16 is active, but to mic/line input 21 if the next layer, CHNS 17-32, is active, and to stereo input 5

if the layer ST CHNS VCA is active.

Every channel parameter for all the channels in a layer retains its last value when

the active layer is changed. This means that all levels, EQ settings, sends, etc.,

adjusted for a particular input will stay exactly as they are when you change to a different layer. Although the fader set and CAM are now assigned to mic/line

inputs 17-32, it is possible to check and adjust parameters in mic/line inputs 1-16

– or any other layer – through the TFT display. Note that as the active layer is

changed, the motorised faders will automatically move to the correct positions for

the new layer.

Revision 1 2012-13 CDC FOUR

CENTRAL CONTROL MODULE

USB

METERS

SCENE

Screen displays - overview

The TFT screen in the Central Control Module displays various information about the current status of the mixer. The screen may be switched to display any one of

several pages, each of which is concerned with a particular set of mixer functions.

There are six pages available, selected by the page select buttons to the left of

the display:

CHN: this is the default view.

ROUTE

SYSTEM

CHN

The screen shows a representation of a single channel strip. Every control on

the CAM has a “virtual” equivalent on the display, and the page layout follows the conventional signal ow through a channel. It is divided into ve vertical strips, the rst four of which follow the layout of controls on the CAM. The fth (rightmost)

page strip shows the channel fader and VCA assignment.

The on-screen display always follows the SEL and LAYER selection; thus the screen provides conrmation of the control settings for the currently selected

channel.

Because the rotary controls in the CAM are 360° encoders, their physical position is not an indication of the parameter value (as would be the case on an analogue

mixer). However, the Channel page shows all current parameter values. Switch

settings are displayed in textual format and rotary controls are represented as “analogue” 300° potentiometers, with the actual parameter value alongside in text.

Revision 1 2012-13CDC FOUR

CENTRAL CONTROL MODULE

USB

METERS

SCENE

ROUTE

SYSTEM

CHN

SYSTEM:

CENTRAL CONTROL MODULE

USB

METERS

SCENE

ROUTE

SYSTEM

This page provides access to various console functions that do not have

equivalent hardware controls. These include line-up oscillator functions, talkback routing control, monitor controls and solo system control. The System page also includes virtual copies of the monitor and headphone level and mute controls,

and the PFL/AFL meters.

See “System” on page 62 for more information.

ROUTE: the Routing page shows a “global” view of all routing assignments for the current layer.

CHN

In addition to the settings of the group and stereo buss routing buttons, the page

also shows the send levels to each of the eight Aux busses and the two FX busses.

See “Routing” on page 51 for more information.

Revision 1 2012-13 CDC FOUR

CENTRAL CONTROL MODULE

USB

METERS

SCENE

ROUTE

SYSTEM

CHN

FX: this page allows control of the CDC FOUR’s two internal FX processors.

CENTRAL CONTROL MODULE

USB

METERS

SCENE

ROUTE

SYSTEM

The processors’ inputs are two “virtual busses”, FX1 and FX2, which can be

used in the same way as any of the Aux sends. The outputs may be routed to the stereo output and their FX return levels controlled by faders 13 and 14 when the OUTPUTS layer is active.

See “FX processing” on page 58 for more information.

SCENE: the Scene page is concerned with the CDC FOUR’s scene memory.

CHN

The CDC FOUR is equipped with a “snapshot”-style scene automation system,

which allows all current console parameters (both switch and rotary control settings) to be saved as a Scene. Scenes may be named and assembled into

a performance sequence off-line, and then, during performance, recalled by

a single button press. This allows the mixer to easily and seamlessly switch

between complex set-ups to suit, for example, successive scenes of a stage drama, or different musical numbers. The motorised faders form part of the scene memory, and when a Scene is recalled, will assume the position they were in

when the Scene was saved.

See “Scene Control” on page 67 for more information.

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CENTRAL CONTROL MODULE

USB

METERS

SCENE

ROUTE

SYSTEM

CHN

METERS: this page gives a “global” overview of up to 50 bargraph meters simultaneously.

The page is divided in to three areas horizontally. The upper area has 16 meters showing the signal level in each of the on-board mic/line channels; the middle area has 8 dual meters showing the signal level in the eight stereo input channels;

the lower area has 12 meters showing the signal levels of the four Groups and

eight Aux sends, and 3 dual meters showing the FX return levels and the stereo

master signal. Metering may be selected pre- or post-fade from the screen.

See “Metering” on page 53 for more information.

Revision 1 2012-13 CDC FOUR

Screen navigation

As channel parameters can be varied both from the TFT display or the CAM, a simple system of screen navigation is provided. On the CHN page, the virtual

control corresponding to the last-adjusted control on the CAM is highlighted by a red rectangular cursor (see left).

The cursor moves around the screen as the various channel controls are adjusted.

Any channel parameter may be adjusted from the screen by moving the cursor to the appropriate virtual control with the four “arrow” keys below the display.

CONTROL

DEL RCLSVE COPY PASTE

ENTER

In general, the “up” and “down” keys will move the cursor vertically within the current strip, and the “left” and “right” keys will move it either to adjacent controls in the same strip or into the next strip. With the desired virtual control highlighted,

its parameter value may be adjusted by the ADJUST knob.

Note that the ADJUST knob is used for both “rotary” functions (EQ adjustments,

send levels, etc.) and switch functions (send pre/post, lters in/out, etc.). Rotary

functions are represented on-screen by a 300° arc, which changes colour clockwise from blue to white as the knob is turned. The actual numeric parameter value is displayed alongside. Switch functions are represented by small rectangular

“buttons”. Status is either indicated by an integral “virtual LED”, which illuminates (white) when the switch is On, or by the text label on the button changing.

If a section of the channel processing is bypassed (e.g., gate, compressor, EQ, etc.), the screen display corresponding to the section is “dark” (greyed-out) to indicate it is not available. See left for example; only AUX 1 and AUX 2 are active.

The same screen navigation principle applies to the other screen pages (with the

exception of the METERS page, which has no controls).

Revision 1 2012-13CDC FOUR

USB

CENTRAL CONTROL MODULE

METERS

SCENE

Softkeys

The CDC FOUR has a set of eight “soft” keys below the screen display. These

have no printed legends; each button’s function is indicated on the TFT screen

immediately above.

ROUTE

SYSTEM

CHN

TALK

ADJUST

In general, the softkeys bring up an additional display page, which presents a section of the current channel in greater detail – e.g., EQ or Dynamics.

Softkeys with a blank legend space above them on the screen have no function.

Revision 1 2012-13 CDC FOUR

Audio channel descriptions

Input channel

A detailed block diagram of the Input channel may be found in the Appendix on page 74.

The CDC FOUR can handle up to 48 mono mic/line inputs, divided into three blocks of 16. The inputs to Channels 1 to 16 are on the rear panel; those for

Channels 17 to 48 are only available if the CDC RACK stagebox is in use.

The CAM and the TFT display are made active for a mic/line input when one of the rst three layers is selected (CHNS 1-16, CHNS 17-24, CHNS 33-48). The active channel is that whose SEL button is illuminated. If no CDC RACK is connected, the two buttons CHNS 17-32 and CHNS 33-48 will be inoperative.

MIC 1

60 0

Mic pre-amps

Mic/line inputs 1 to 16 are equipped with high-quality, low-noise mic pre-amps.

This design uses premium ICs and exhibits wide dynamic range and excellent CMRR. The gain control operates in the analogue domain, and has a range of 0 to +60 dB.

Meters

The 10-segment LED bargraph meter shows either the pre-fade or post-fade

signal in the channel, as selected by the Pre/Post switch on the METERS screen page. The sixteen xed meters (below the mic pre-amp gain controls) change source with layer selection, thus can be used to monitor stereo inputs, group and Aux sends, etc., as well as mic/line inputs. When the ST CHNS VCA layer is selected, the odd numbered meters show the left legs of the stereo channels, and

the even-numbered the right.

The lowest LED (coloured green) illuminates at -54 dB and can be considered a “signal present” LED. The top three LEDs (coloured red) illuminate at -6 dB,

-3 dB and 0 dB respectively. Note that the 0 dB reference for these levels is 0 dBFS (digital clipping). Thus the input gain should be adjusted so that the top LED never illuminates.

Revision 1 2012-13CDC FOUR

GATE

THR

Remainder of input channel - CAM/screen control

All other input channel functions are controlled from either the CAM or the screen.

In CHN mode, the screen displays a virtual channel strip with a full set of controls

which may be adjusted using the ADJUST knob.

TRIM

HPF

GATE

THR

48V

REV

HPF

Input stage:

TRIM - input gain trim, range -48 to +12 dB. Default setting is 0 dB.

48v – enables 48 V phantom power at the mic input. Default is Off.

REV – phase reverse switch. Default is Off.

HPF (button) – enables the variable-frequency high-pass lter. Default is Off.

HPF (rotary) – adjusts the cut-off frequency of the high-pass lter. Range is 14 Hz

to 400 Hz, slope 12 dB/oct. Default setting is the minimum: 14 Hz.

Noise gate:

THR – adjusts the threshold of the channel’s noise gate in the range from “off”

(below -74.9 dB) to -20 dB. Default setting is -60 dB. When the gate is in circuit, signals below the threshold level will be rejected; the signal level needs to exceed

the threshold in order to open the gate.

IN – switches the noise gate into the signal chain. Default is Out.

NOTE: Additional Gate parameters are available from the Dynamics Details screen page – see “Dynamics detail” on page 54.

COMP

THR

20:11:1

RAT

LVL

AUT

VIN

Compressor:

THR – adjusts the threshold of the channel’s compressor in the range -48 dB to 0 dB. Default setting is -12 dB. Signals below the threshold will not be compressed. Signals above the threshold will have their levels reduced to a degree determined by the ratio control (below).

RAT – adjusts the compression ratio between 1:1 to 20:1. Default setting is 1:1

(i.e., no compression). A compression ratio of 1:1 implies zero compression; higher values will proportionately reduce the dynamic range of the signal, e.g., at a setting of 2:1, signals 10 dB above the threshold will be compressed to be only

5 dB above the threshold.

LVL – adds gain to compensate for compressor action. Range is -12 dB to +12 dB. Default setting is 0 dB.

IN – switches the compressor into the signal chain. Default is Out.

AUT – in Auto mode, the compressor’s Attack and Release time constants are

not xed, but programme-dependent, and set by an algorithm which makes the compressor’s action unobtrusive. In Manual mode, the time constants may be

adjusted from the Dynamics Detail page (see NOTE below).

Revision 1 2012-13 CDC FOUR

DLY

SmS

20:11:1

LIM

THR

DLY

COMP

GATE

LVL

RAT

THR

AUT

VIN

SmS

VIN – enables an alternative compressor algorithm which makes the compressor

act like a leveller, modelling the sound of certain vintage compressors.

NOTE: Additional Compressor parameters are available from the Dynamics Details screen page – see “Dynamics detail” on page 54.

Delay section:

DLY – the CDC FOUR allows an adjustable delay to be inserted in each signal

channel. Range 0 to 100 ms. Default setting is zero.

DLY: IN - switches the delay circuit into the signal chain. Default is Out.

BYP PST

Dynamics/Delay Global:

BYP - switches the complete dynamics section (gate, compressor and limiter) and delay section in and out of the signal chain. Default is Out.

PST – the dynamics and delay sections can be pre- or post-EQ in the CDC FOUR.

Pressing PST inserts them after the equaliser. Default is Off (i.e., dynamics are pre-EQ).

Revision 1 2012-13CDC FOUR

HI LO

FREQ

HI LO

FREQ

HMF

HI LO

FREQ

HMF

LMF

EQ Section:

The CDC FOUR’s equaliser is a 4-band parametric type, with bell-shelf switching

on the highest and lowest bands. The channel’s frequency response (EQ curve) can be seen on the EQ detail page (see page 54).

IN – switches the HF section of the equaliser into circuit. Default is Out.

HI LO

FREQ

HI LO

FREQ

HMF

FREQ – adjusts the frequency of the HF section of the equaliser. This will be the

centre frequency of a bell lter if the Shelf switch is set to Bell, and the turnover frequency if it is set to Shelf. Range is 1.5 kHz to 15 kHz. Default setting is 1.5

kHz.

GAIN – allows 18 dB of cut or boost in the selected frequency band. Default

setting is 0 dB (at response).

Q – adjusts the bandwidth of a bell lter; Q range is 1.0 (wide) to 3.0 (narrow).

Default setting is 1.0. If the Shelf switch is On, the control is inoperative and is removed from the screen display.

Shelf – switches the HF section of the equaliser between Bell and Shelving

modes. In Shelving mode, the EQ section acts as a “treble” control, and has a xed slope of 6 dB/octave. Default is Bell.

IN – switches the HMF section of the equaliser into circuit. Default is Out.

FREQ – adjusts the frequency of the HMF section of the equaliser. The section is

always a Bell lter. Range is 400 Hz to 4 kHz. Default setting is 400 Hz.

GAIN – allows 18 dB of cut or boost in the selected frequency band. Default

setting is 0 dB (at response).

FREQ

LMF

FREQ

HI LO

Q – adjusts the bandwidth of the lter; Q range is 1.0 (wide) to 3.0 (narrow).

Default setting is 1.0.

IN – switches the LMF section of the equaliser into circuit. Default is Out.

FREQ – adjusts the frequency of the LMF section of the equaliser. The section is

always a Bell lter. Range is 60 Hz to 600 Hz. Default setting is 60 Hz.

GAIN – allows 18 dB of cut or boost in the selected frequency band. Default

setting is 0 dB (at response).

Q – adjusts the bandwidth of the lter; Q range is 1.0 (wide) to 3.0 (narrow).

Default setting is 1.0.

IN – switches the LF section of the equaliser into circuit. Default is Out.

FREQ – adjusts the frequency of the LF section of the equaliser. This will be the

centre frequency of a bell lter if the Shelf switch is set to Bell, and the turnover frequency if it is set to Shelf. Range is 20 Hz to 200 Hz. Default setting is 20 Hz.

GAIN – allows 18 dB of cut or boost in the selected frequency band. Default

setting is 0 dB (at response).

Q – adjusts the bandwidth of a bell lter; Q range is 1.0 (wide) to 3.0 (narrow).

Default setting is 1.0. If the Shelf switch is On, the control is inoperative and is removed from the screen display.

Revision 1 2012-13 CDC FOUR

Shelf – switches the LF section of the equaliser between Bell and Shelving

HI LO

FREQ

HMF

LMF

modes. In Shelving mode, the EQ section acts as a “bass” control, and has a xed slope of 6 dB/octave. Default is Bell.

AUX 1

AUX 2

AUX 3

AUX 4

AUX 5

AUX 6

AUX 7

AUX 8

∞

PRE

EQ IN – switches the entire 4-band EQ section into circuit. Default is EQ Out; in this state, the entire EQ section of the CHN page is “dark”.

Aux Sends:

The CDC FOUR’s eight auxiliary sends are identical in operation. For brevity,

only Aux 1 is described:

∞

PRE

∞

PRE

∞

PRE

∞

PRE

∞

PRE

∞

PRE

∞

PRE

AUX 1 – level control from the channel to Aux Buss 1. Range is – ∞ (i.e., off); then

-75 dB to 0 dB. Default is Off.

ON – unmutes the feed to Aux Buss 1. Default is Off.

PRE – default source for Aux. Sends is post-fade, but can be changed to pre-fade

with the PRE button. Both pre- and post-fade sends are post-Channel Mute.

The status of all eight Aux. sends for blocks of 16 input channels may be viewed on the screen ROUTE page. See page 51.

Revision 1 2012-13CDC FOUR

FX Sends:

FX 1

∞

PRE

FX 2

∞

PRE

LRGR

PAN

LIM

The CDC FOUR has two internal DSP-based effects processors, which provide

a selection of time-domain effects such as delay and reverb. The inputs to these

are additional sends, denoted FX1 and FX2, and the outputs are routed to the

main LR stereo buss or Groups 1 to 4 via two faders in the OUTPUTS Layer. See “FX processing” on page 58 for full details.

The two FX sends are identical in operation. For brevity, only FX 1 is described:

FX 1 – level control from the channel to internal FX buss 1. This routes the signal to FX processor 1. The level control’s range and default settings are the same as the Aux. sends.

ON – unmutes the feed to FX Send 1. Default is Off.

PRE – default source for FX Send is post-fade, but can be changed to pre-fade with the PRE button. Both pre- and post-fade sends are post-Channel Mute.

Routing and metering section:

The CDC FOUR has four mono group busses in addition to the main LR stereo buss. The groups may either be used as subgroups into the main mix or as additional outputs from the mixer. The usual set of routing buttons and odd/even panning is provided.

1 - 4 – four buss select buttons which route the channel to Audio Groups 1 to 4 respectively.

L & R – two buss select buttons which route the channel respectively to the L and R legs of the stereo master buss. Note that the pan control is always in circuit with

respect to the L & R busses.

PAN – allows the channel signal to be panned between odd-numbered busses (and the L leg of the master buss) and even-numbered busses (and the R leg of

the master buss). Default is “centre” – i.e., equal signal levels are routed to the

selected busses. The adjacent IN button must be enabled for the pan control to

be active for the four groups; it is always operational across the main L/R buss.

IN – enables the PAN control for panning between odd- and even-numbered groups. Default is Out; in this state, the signal in the channel is sent at equal level to all busses selected by the routing buttons 1 to 4.

L & R METERS – two 10-segment LED bargraph meters indicating channel

signal level are tted in the CAM area. With mic/line channels, both L and R

meters give the same indication. The meters show the pre-fade (and hence prepan) signal level relative to 0 dBFS. The bottom LED is green and illuminates at

-54 dBFS, and thus acts as a “signal present” LED. The top three LEDs are red,

the uppermost indicating the digital peak level of 0 dBFS. The remainder of the LEDs are yellow.

GR METER – an 8-segment LED bargraph meter indicating the instantaneous gain reduction being applied by the dynamics section’s compressor.

GT – a red LED which illuminates when the channel’s Noise Gate is opened by the signal exceeding the threshold.

Revision 1 2012-13 CDC FOUR

LIM – non-operative for input channels.

Mute and Solo:

SOLO

MUTE

SOLO – routes the signal in the channel to the internal PFL or AFL busses,

to permit the signal to be monitored without otherwise interrupting the mixer’s routings. The operation of the Solo system is controlled from the Solo Logic section, see “Solo control” on page 63.

MUTE – mutes the signal in the channel. Note that all Aux. Sends are also muted,

but Insert Sends and Direct Outs remain active.

Note that the CAM’s MUTE and SOLO buttons have exactly the same function as the fader block MUTE and SOLO buttons for the channel currently assigned to the CAM (i.e., those immediately below whichever SEL button is currently illuminated).

Revision 1 2012-13CDC FOUR

Stereo inputs

A detailed block diagram of the Stereo Inputs may be found in the Appendix on page 75.

The CDC FOUR has eight stereo line channels, with inputs on the rear panel.

The CAM and the TFT display are made active for a stereo channel when the ST CHNS VCA layer is selected. The stereo channels are then controlled by

Faders 1 to 8, and that assigned to the CAM and TFT display is the one whose

SEL button is illuminated.

Analogue mixers generally offer a more limited set of controls on stereo channels

than on mono. This need not apply to a digital mixer, and on the CDC FOUR, a

stereo line channel has almost the same set of controls as a mono channel.

For this reason, only the differences from a mono channel are summarised

below. The description of the mono mic/line channel applies in all other respects. Refer to Page 32 onwards for full details.

Input stage:

TRIM - input gain trim, range -48 to +12 dB. Default setting is 0 dB.

Phase reverse – reverses the phase in the left leg of the channel only.

Aux Sends:

In a stereo channel, a mono sum of left and right legs is fed to the auxiliary

busses. The send controls otherwise operate in an identical manner to those

in a mono channel. Post-fade sends are derived pre-balance control, but post-

Channel mute.

Routing and metering section:

The left and right legs of a stereo channel are fed to the L and R busses of the

main stereo mix via the pan control, which is recongured to operate as a stereo

balance control.

With the pan control IN button Off, pressing any of the group routing buttons 1 to 4 sends a mono sum of the left and right legs to that group; routing to multiple groups will operate in the same way. If the pan IN button is On, stereo routing to odd/even pairs of groups results. The stereo image set by the balance control

is maintained, with the left leg selectable to Groups 1 and 3, and the right leg to

Groups 2 and 4.

Pan – acts as a balance control; turning the control clockwise from the centre

position will attenuate the left leg of the channel but leave the right leg unaltered

in level. At the maximum, the left leg is fully attenuated. The opposite applies for

anticlockwise rotation.

Revision 1 2012-13 CDC FOUR

Groups

A detailed block diagram of the Groups may be found in the Appendix on page 76.

The CDC FOUR has four mono groups, with outputs on the rear panel. They may be used either for recording or other external purposes, or the outputs may be ignored, and they can form subgroups into the main stereo mix.

Some channel functions are absent from groups (relative to the input channels). The differences from a mono channel are summarised below. The description of the mono mic/line channel applies in all other respects. Refer to Page 32 onwards for full details.

Input stage:

All input functionality is removed. The Input Trim, high-pass lter and phase

controls are inoperative and their virtual counterparts do not appear on-screen.

Noise gate:

The groups do not have noise gates. All noise gate controls are inoperative and their virtual counterparts do not appear on-screen.

Limiter:

The groups’ dynamics sections have a dedicated limiter as well as the compressor

section tted to the input channels.

THR - adjusts the threshold of the group’s separate limiter section in the range

-40 dB to +21 dB. Default setting is +21 dB (i.e., no limiting).

IN - switches the limiter into the signal chain. Default is Out.

Aux Sends:

The groups do not have Aux Send facilities. All Aux Send controls are inoperative and their virtual counterparts do not appear on-screen.

Revision 1 2012-13CDC FOUR

FX Sends:

The groups cannot send to the internal FX processors. All FX Send controls are inoperative and their virtual counterparts do not appear on-screen.

Routing and metering section:

Any of the four groups may be routed to the main LR stereo buss, permitting their

use as subgroups. The groups default with this routing enabled. The PAN control

is always in circuit, and with the control at its centre position (50/50, the default value), the mono group signal feeds the left and right legs of the main stereo buss equally, and is thus in the centre of the main stereo image. Full left-right panning is possible, using either the PAN control on the CAM or via the screen using the

ADJUST control. However, the pan control IN button is disabled.

1 - 4 – the four group routing buttons 1 to 4 are not available to groups; thus it is

not possible to route a group to another group (or itself!).

L & R – a group may be routed to either the left or right legs of the main stereo

buss individually, though the setting of the PAN control will affect the level (i.e.,

routing to L and panning fully right will result in no signal).

Revision 1 2012-13 CDC FOUR

VCA groups

Although the CDC FOUR, as a digital mixer, has no actual VCAs – these being a

purely analogue concept – the terminology is retained for reasons of familiarity.

The CDC FOUR allows the creation of up to eight “control groups”, which

operate in exactly the same way as VCA groups on an analogue mixer. Any input channel (mono or stereo) may be assigned to any VCA group or combination of VCA groups. The level of all the channels in the group may then be adjusted simultaneously by a single fader.

The VCA master faders are available when the ST CHNS VCA layer is selected; faders 9 to 16 are assigned for this purpose. Note that as VCA groups are entirely

“virtual”, they are not assigned to the CAM. When the ST CHNS VCA layer is selected, pressing a SEL button above any of the VCA faders opens a dedicated VCA screen page, which gives an overview of the VCA master fader settings.

Note that this page may also be viewed at any time by the use of Softkey 7, which is available on all input and output pages.

VCA group assignment

Any mono or stereo input channel may be assigned to any combination of VCA

groups. The assignment is made via the display; there are no equivalent hardware

keys. The VCA group buttons are at the extreme right of the Channel page and

may be selected by moving the cursor to them with the navigation keys, and

operated by rotating the ADJUST knob.

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Levels within VCA groups

As with all layers, when the ST CHNS VCA layer is selected, faders 9 to 16

immediately move to their correct positions. If no adjustment of VCA master levels

have been made, this position will be at the 0 dB mark. The implication of this

is that simply assigning a channel to a VCA group does not alter its signal level anywhere in the mixer. The level in the mix may now be adjusted in two places – by the channel’s own fader or by the VCA master. The fader positions of the two

faders effectively “add” to dene the overall signal level. Thus if the channel fader is at -6 dB and the VCA fader is set to -10 dB, the level of the channel in the mix

will be the same as it would if the channel fader were set to -16 dB without any VCA assignment being made.

The relative levels of all the channels assigned to any one VCA group remain

unchanged; adjusting the VCA master alters the level of the whole set of

channels without disturbing their inherent mix. A common application is to assign all the channels being used to mic a drum kit to a VCA group after a satisfactory balance of the kit has been made. The VCA master fader will then alter the level

of the whole kit in the mix, without altering any the internal balance, or any stereo

imaging.

VCA Group Muting

A VCA group may be muted by pressing the MUTE button above the VCA master fader. This mutes all the channels assigned to the group. A corresponding virtual MUTE button is provided on the TFT VCA page. The individual channels’ MUTE buttons – both the physical ones and the on-screen virtual buttons – illuminate to

conrm this.

Note that the SOLO button has no function for a VCA group.

Revision 1 2012-13 CDC FOUR

Aux outputs

A detailed block diagram of the Aux 0utputs may be found in the Appendix on page 77.

The CDC FOUR has eight auxiliary sends, with outputs on the rear panel. All the sends are mono. They may be used for external FX sends, or for foldback

purposes.

The Aux Send channels have processing similar to that of the Groups; the main

difference is the absence of any routing. The differences from a mono channel are summarised below. The description of the mono mic/line channel applies in all other respects. Refer to Page 32 onwards for full details.

Input stage:

All input functionality is removed. The Input Trim, high-pass lter and phase

controls are inoperative and their virtual counterparts do not appear on-screen.

Noise gate:

The Aux Send channels do not have noise gates. All noise gate controls are inoperative and their virtual counterparts do not appear on-screen.

Limiter:

The Aux Sends’ dynamics sections have a dedicated limiter as well as the

compressor section tted to the input channels.

THR - adjusts the threshold of the Aux send’s separate limiter section in the range

-40 dB to +21 dB. Default setting is +21 dB (i.e., no limiting).

IN - switches the limiter into the signal chain. Default is Out.

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Aux Sends:

It is not possible to send an Aux output to another Aux Send. All Aux Send controls are inoperative and their virtual counterparts do not appear on-screen.

FX Sends:

The Aux outputs cannot send to the internal FX processors. All FX Send controls are inoperative and their virtual counterparts do not appear on-screen.

Routing and metering section:

It is not possible to route an Aux output anywhere else, thus the routing buttons 1 to 4 and L & R are inoperative. As the sends are mono, the PAN controls are also inoperative. MUTE and SOLO are still functional, however.

Revision 1 2012-13 CDC FOUR

STEREO MASTER OUTPUT MODULE

LRGR

COMP

THR

20:11:1

RAT

LVL

LIM

THR

BYP

AUT

VIN

PST

LIM

HI LO

FREQ

HI LO

FREQ

HMF

HI LO

FREQ

LMF

HI LO

FREQ

Stereo master

A detailed block diagram of the Stereo master may be found in the Appendix on page 78

The stereo master channel on the CDC FOUR differs from all the other channel

types in several respects, most importantly, the absence of a SEL button, and the

provision of a dedicated set of controls. The controls and facilities on the Stereo Master Output Module (SMOM) are very similar to those which the CAM provides to the other channel types.

The TFT screen can be selected to display the stereo master channel by pressing Softkey 8 from any other page:

Derived outputs

The main stereo outputs from the left and right leg D-to-A converters in the stereo master output channel are also routed internally to the stereo tape outputs (TAPE L OUT and TAPE R OUT) and the mono sum output (MONO). All outputs are fully buffered from each other.

The stereo tape outputs provide an identical balanced signal to that at the stereo

master outputs, except that 3-pole ¼” jacks are used.

The mono sum is a balanced (L+R) - 6dB sum of the master stereo output.

The facilities of the Stereo Master Output Module are as follows:

Revision 1 2012-13CDC FOUR

HI LO

FREQ

HMF

LMF

STEREO MASTER OUTPUT MODULE

LIM

LRGR

20:11:1

HI LO

FREQ

COMP

LVL

RAT

THR

HMF

LMF

STEREO MASTER OUTPUT MODULE

LIM

LRGR

AUT

VIN

20:11:1

HI LO

FREQ

LIM

THR

COMP

LVL

RAT

THR

HMF

LMF

STEREO MASTER OUTPUT MODULE

LIM

LRGR

AUT

VIN

COMP

THR

20:11:1

RAT

LVL

LIM

THR

BYP

Compressor:

THR - adjusts the threshold of the channel’s compressor in the range -48 dB to 0 dB. Default setting is -12 dB.

AUT

VIN

RAT - adjusts the compression ratio between 1:1 to 20:1. Default setting is 1:1

(i.e., no compression).

LVL – adds gain to compensate for compressor action. Range is -12 dB to +12 dB. Default setting is 0 dB.

IN – switches the compressor into the signal chain. Default is Out.

AUT – in Auto mode, the compressor’s Attack and Release time constants are

not xed, but programme-dependent, and set by an algorithm which makes the

compressor’s action unobtrusive. In Manual mode, the time constants may be adjusted from the Dynamics Detail page (see NOTE below).

VIN – enables an alternative compressor algorithm which makes the compressor

act like a leveller, modelling the sound of certain vintage compressors.

NOTE: Additional Compressor parameters are available from the Dynamics Details screen page – see page 54.

PST

Limiter:

THR - adjusts the threshold of the master output’s separate limiter section in the range -40 dB to 0 dB. Default setting is 0 dB.

IN - switches the limiter into the signal chain. Default is Out.

Dynamics Global:

BYP

PST

BYP - switches the complete dynamics section (compressor and limiter) in and out of the signal chain. Default is Out.

PST – the dynamics section can be pre- or post-EQ. Pressing PST inserts it after

the equaliser. Default is Off (i.e., dynamics are pre-EQ).

EQ Section:

The CDC FOUR’s stereo master channel is equipped with a 4-band parametric

equaliser, with bell-shelf switching on the highest and lowest bands. The channel’s

frequency response (EQ curve) can be seen on the EQ detail page (see page

54).

HI LO

FREQ

Revision 1 2012-13 CDC FOUR

IN – switches the HF section of the equaliser into circuit. Default is Out.

FREQ – adjusts the frequency of the HF section of the equaliser. This will be the

centre frequency of a bell lter if the Shelf switch is set to Bell, and the turnover frequency if it is set to Shelf. Range is 1.5 kHz to 15 kHz. Default setting is 1.5

kHz.

GAIN – allows 18 dB of cut or boost in the selected frequency band. Default

setting is 0 dB (at response).

Q – adjusts the bandwidth of a bell lter; Q range is 1.0 (wide) to 3.0 (narrow).

Default setting is 1.0. If the Shelf switch is On, the control is inoperative and is removed from the screen display.

Shelf – switches the HF section of the equaliser between Bell and Shelving

HI LO

FREQ

HI LO

FREQ

HMF

HI LO

FREQ

HMF

LMF

HI LO

FREQ

HMF

LMF

modes. In Shelving mode, the EQ section acts as a “treble” control, and has a xed slope of 6 dB/octave. Default is Bell.

HI LO

FREQ

HMF

HI LO

FREQ

LMF

IN – switches the HMF section of the equaliser into circuit. Default is Out.

FREQ – adjusts the frequency of the HMF section of the equaliser. The section is

always a Bell lter. Range is 400 Hz to 4 kHz. Default setting is 400 Hz.

GAIN – allows 18 dB of cut or boost in the selected frequency band. Default

setting is 0 dB (at response).

Q – adjusts the bandwidth of the lter; Q range is 1.0 (wide) to 3.0 (narrow).

Default setting is 1.0.

IN – switches the LMF section of the equaliser into circuit. Default is Out.

FREQ – adjusts the frequency of the LMF section of the equaliser. The section is

always a Bell lter. Range is 60 Hz to 600 Hz. Default setting is 60 Hz.

GAIN – allows 18 dB of cut or boost in the selected frequency band. Default

setting is 0 dB (at response).

Q – adjusts the bandwidth of the lter; Q range is 1.0 (wide) to 3.0 (narrow).

Default setting is 1.0.

FREQ

HI LO

IN – switches the LF section of the equaliser into circuit. Default is Out.

FREQ – adjusts the frequency of the LF section of the equaliser. This will be the

centre frequency of a bell lter if the Shelf switch is set to Bell, and the turnover frequency if it is set to Shelf. Range is 20 Hz to 200 Hz. Default setting is 20 Hz.

GAIN – allows 18 dB of cut or boost in the selected frequency band. Default

setting is 0 dB (at response).

Q – adjusts the bandwidth of a bell lter; Q range is 1.0 (wide) to 3.0 (narrow).

Default setting is 1.0. If the mode is set to Shelf, the control is inoperative and is removed from the screen display.

Shelf – switches the LF section of the equaliser between Bell and Shelving

modes. In Shelving mode, the EQ section acts as a “bass” control, and has a xed slope of 6 dB/octave. Default is Bell.

EQ IN – switches the entire 4-band EQ section into circuit. Default is EQ Out; in this state, the entire EQ section of the CHN page is “dark”.

Revision 1 2012-13CDC FOUR

HI LO

FREQ

STEREO MASTER OUTPUT MODULE

LRGR

LIM

Metering section:

L & R METERS – two 10-segment LED bargraph meters indicating the signal

level of the stereo master output are tted in the Stereo Master Output Module area. The meters show the post-fade signal level relative to 0 dBFS – i.e., the

main stereo signal leaving the mixer. The bottom LED is green and illuminates at

-54 dBFS, and thus acts as a “signal present” LED. The top three LEDs are red,

the uppermost indicating the digital peak level of 0 dBFS. The remainder of the LEDs are yellow.

GR METER – an 8-segment LED bargraph meter indicating the instantaneous gain reduction being applied by the dynamics section’s compressor.

GT – not used.

LIM – a red LED which illuminates when the signal in the channel exceeds the

limiter threshold.

Mute and Solo:

SOLO – routes the stereo master signal to the internal AFL buss, to permit

the signal to be monitored without otherwise interrupting the mixer’s routings. The operation of the Solo system is controlled from the Solo Logic section, see page 63.

MUTE – mutes the master stereo output, the mono sum output and the stereo

tape output. To be used with caution!

Revision 1 2012-13 CDC FOUR

FX sends and returns

The two FX channels in the CDC FOUR differ from the other channel types in that they are entirely internal to the mixer and have no external signal inputs or outputs.

As shown in the channel descriptions above, all mono and stereo input channels are able to send to the two internal FX busses, FX 1 and FX 2, via the dedicated controls on the CAM, or their virtual on-screen equivalents. The signals on the FX

busses are summed in the normal way (though wholly in the digital domain) and may have EQ and dynamics applied in the same way as other types of channel. The

signal is then passed to a DSP FX processor, which can add time-domain effects

such as reverb and delay. (See “FX processing” on page 58 for more details of the effects themselves). The processed signal (now in stereo) is then available to be fed back into the mix (and elsewhere) via the two FX return faders FX 1 and

FX 2; these are faders 13 and 14 in the OUTPUTS layer. This process is exactly analogous to patching in an external FX unit to an analogue mixer, where an

Aux send would be used to send a signal from one or more channels to the FX

unit, and the unit’s output would be brought back into the mixer via dedicated FX returns or spare channels as available, or desired.

The CAM and the TFT display are available to an FX channel when the OUTPUTS layer is selected. Pressing the SEL button above one of the faders assigns the FX channel to the CAM and screen.

On the CDC FOUR, the FX channels have an almost identical set of controls to a mono channel, although they are treating a stereo signal; this includes EQ, routing and Aux sends. For this reason, only the differences from a mono channel

are summarised below. The description of the mono mic/line channel applies in all other respects. Refer to Page 32 onwards for full details.

Input stage:

All input functionality is removed. The Input Trim, high-pass lter and phase

controls are inoperative and their virtual counterparts do not appear on-screen.

Revision 1 2012-13CDC FOUR

Noise gate:

The FX sends do not have noise gates. All noise gate controls are inoperative and their virtual counterparts do not appear on-screen.

FX Sends:

It is not possible to send the signal in an FX return back into an FX send. The FX send controls are inoperative and their virtual counterparts do not appear onscreen.

Revision 1 2012-13 CDC FOUR

ADJUST

TALK

CENTRAL CONTROL MODULE

USB

METERS

SCENE

ROUTE

SYSTEM

CHN

Other screen pages

The TFT screen has several further pages available; some of these are selected

by the buttons to the left of the display:

Two further “Detail” pages – EQ Detail and Dynamics Detail are opened from Softkeys on the Channel Overview page.

Channel

The Channel pages displayed for the various types of channel have already been described in detail. The Channel page for the currently selected channel (the one in the current layer with its SEL button illuminated) may be displayed at any time by pressing the CHN button.

Routing

The ROUTE button opens the Routing screen page.

The page is arranged in tabular form, with channels as rows. The columns represent, from left to right, routing status to Groups 1 to 4 (G1 – G4) and the left and right legs of the main stereo output (L and R); these may be displayed as ON

or off; followed by the send level to each of the eight Aux busses (A1 - A8) and the two internal FX sends (FX1 and FX2). The send levels are displayed directly in dBs relative to “full level”, with – ∞ indicating ‘off’, and a level range of -75 to 0. Note that the level is followed by an asterisk (*) if the send is selected pre-fade.

Inactive routings appear in black. When a routing button on the CAM is pressed, the corresponding routing ag turns blue and the legend changes. The Aux and

FX sends are black when the send is not enabled by its ON button, and turns blue when it is pressed. Note that the actual send level is still displayed when the send is OFF; this allows a send level to be preset but the send itself muted until

required, as would be the case with an analogue mixer.

Revision 1 2012-13CDC FOUR

As with the CHN page, the arrow keys may be used to navigate the cursor around

the page, and the ADJUST knob used to set the routing to the L/R and Group busses, and to adjust Aux Send or FX Send levels. This is a useful feature as

it permits send levels to be set for multiple channels without assigning them successively to the CAM.

Similar pages are presented for the CHNS 17-32 and CHNS 33-48 layers, providing that a CDC RACK stagebox is connected. If the ST CHNS VCA layer is

active, the Routing page shows the routings for the eight stereo channels:

If the OUTPUTS layer is active, the Routing page shows the routings for Groups 1 to 4 and the two FX channels FX1 and FX2:

Note that this page displays the reduced set of routings that are permitted for

outputs; Groups can only be routed to the main stereo output, FX return channels cannot be routed back to themselves, and Aux channels have no routing possibilities at all, and are thus not included on the page.

Revision 1 2012-13 CDC FOUR

Metering

The METERS button opens the Metering page. This allows the signal levels in all the CDC FOUR’s internal channels to be viewed simultaneously. The meters displayed on the Metering page are “virtual copies” of the meters on the Channel Overview pages.

The screen is divided into three, with input meters at the top and centre and output meters at the bottom. Channels 1 to 16 are displayed at the top, the eight stereo channels as dual meters in the centre, and meters for the four Groups, eight Aux sends, two FX sends and the stereo master at the bottom. The FX

sends and stereo master have dual meters.

The middle and lower areas are constant, but the upper area will change with selection of the higher-numbered input channel layers (17-32 and 33-48), if the

CDC RACK stagebox is in use.

The metering source for the mono and stereo channels may be switched between pre- or post-fade by Softkeys 1 and 2 respectively. Two further softkeys select the output meters (the bottom meter panel) to switch pre- or post-fade in a similar manner.

Revision 1 2012-13CDC FOUR

EQ detail

This page is opened by pressing Softkey 2 from any Channel Overview page. It provides a graphical representation of the currently selected channel’s equaliser response.

The EQ curve is displayed as a conventional frequency response graph, with a logarithmic frequency scale from 20 Hz to 20 kHz. The EQ section’s virtual controls are included on the screen; the cursor and navigation keys may be used

to adjust the EQ response instead of the CAM if preferred. As with the Channel

Overview page, the EQ responses of each channel may be viewed and compared

by pressing each channel’s SEL button in turn.

Dynamics detail

This page is opened by pressing Softkey 1 from any Channel Overview page. It provides a graphical representation of the transfer characteristic of the currently selected channel’s compressor.

Revision 1 2012-13 CDC FOUR

The dynamics section’s virtual controls are included on the screen; the cursor

and navigation keys may be used to adjust dynamics parameters instead of the CAM if preferred. The Dynamics detail page differs from the EQ detail page in the important respect that additional dynamics parameters are available for

adjustment. These parameters cannot be accessed from the CAM, but may be

adjusted using the cursor and ADJUST controls.

Noise Gate

In addition to the Threshold (THR) and Gate In (IN) controls that are available

from the CAM and Channel Overview page, the Dynamics detail page provides

the following controls:

Depth – adjusts the attenuation applied to signals below the threshold. The range

is 0 dB to 96 dB, with a default setting of 80 dB. Setting a lower Depth parameter causes the gate to only “partially close”, and not fully reject signals whose level

is below the gate threshold.

Hold – a noise gate’s action can be obtrusive if it closes too suddenly when the signal drops below the threshold level. The Hold and Release (see below) parameters control this timing. Hold is variable between 2 ms and 2 s, and has a

default setting of 2 ms. When the signal level drops below the threshold, the gate

remains open for the Hold time before the gate begins to close again.

Release – sets the time over which the gate attenuates the signal (to the level set by Depth) after the expiry of the Hold time. It has a range of 2 ms to 2 s, with a

default setting of 350 ms, which is a suitable value for many musical sources. The attenuation increases linearly over the Release period, minimising the audible

effect of the gate closing.





















Compressor

Threshold, Ratio and Level parameters, plus Compressor In, Manual/Auto and Standard/Vintage settings are available from the CAM and Channel Overview

page. In addition to these, the Dynamics detail page also provides the following

controls:

Attack – this is a time parameter which determines how rapidly compression is applied to signals once they have exceeded the value set by the Threshold

control. With some percussive sounds, applying compression too quickly removes the initial transient of the signal, which can rob it of its character. The range of times available is 0.5 ms to 100 ms; the default value is 25 ms.

Revision 1 2012-13CDC FOUR

Release – this works in a similar manner to the Noise Gate’s Release

parameter; after the signal level drops below the compressor threshold,

the gain reduction applied as a result of the compressor action is gradually reduced. Setting the Release parameter to suit the signal being treated will generally minimise the effect of “pumping” that compression can produce.

Transfer Characteristic and meters

The Dynamics detail page also provides separate input and output metering for

the gate, compressor and limiter (in the case of the Groups and Aux Sends), which

allows a quick evaluation to be made of the effects of the dynamics processing. A Gain Reduction meter for the compressor is also implemented on-screen.

The transfer characteristic displays the relationship between input and output levels graphically, and shows the effects of the compressor’s Threshold, Ratio and Level controls. The horizontal (x-) axis represents input signal levels, and the vertical (y-) axis output levels. The output signal level for any input signal level can be found by tracing a line vertically from the x-axis at the point representing

the input signal level to the transfer curve, then reading across horizontally to the

y-axis.

-20

Output level = -23 dB

-40

-60

A B

-40

THRESHOLD

-20

Input level = -10 dB

With no compressor action (i.e., with the compressor by-passed, or with Ratio set to 1:1), the transfer characteristic is a straight line at 45° to both axes. The line becomes “kinked” when compression is applied. In the example above, the input signal at A is at -35 dB, and hence below the threshold of -30 dB; no compression

Revision 1 2012-13 CDC FOUR

is applied, and the output level is also -35 dB. The signal level at B is -10 dB,

which is above the threshold. This results in the output level being reduced by 13

dB to -23 dB. Real world signals, of course, have a dynamic range which includes elements both above and below the threshold, so the effect of compression is only for the louder elements to be reduced in level, which will reduce the overall

volume. This reduction can be compensated for with the Level control.

As with the Channel Overview page, the dynamics processing of each channel

may be viewed and compared by pressing each channel’s SEL button in turn.

Revision 1 2012-13CDC FOUR

FX processing

The FX button opens the FX Settings page; the two internal DSP effects processors are controlled from here. The two processors each have their own (identical)

control page; Softkeys 4 and 5 select that for FX1 and FX2 respectively. The controls on these pages have no hardware equivalents, and are selected and are

adjusted by using the cursor keys and the ADJUST control.

Each FX processor comprises three separate FX “modules”: Reverb, Delay and

Modulation.

The default input signal to each FX module is the signal being sent to the FX1 (or FX2) buss. This is indicated by the Input buttons, which may alternatively be set to Off to disable the effect of that module, or to the other FX buss, or to any of

the eight Aux busses. The three modules are effectively “in parallel”, and may be used individually, or in combination. Alternatively, the modules may be connected “in series” using the Send controls in the Modulation and Delay modules. Thus, the Modulation module may feed either the Delay or Reverb modules, with the Reverb or Delay module remaining free to be used with another source; or all

three modules may be cascaded.

The outputs of the two FX processors can be added to the Stereo Master mix, or to any of the four Groups, by using faders 13 and 14 in the Outputs layer. See

“FX sends and returns” on page 49 for full information on the audio path of the FX channels.

Module 1 - Modulation

The Modulation module may be used to generate a range of time-variant “phasing”

effects of various kinds. 8 standard modulation presets are provided, which may

be selected with the Preset control. These are:

Chorus Slow Chorus Fast Flanger Slow Flanger Fast Celeste Slow Celeste Fast Rotor Slow

Revision 1 2012-13 CDC FOUR

Rotor Fast

Once a Preset has been selected, the effect may be modied as required by

adjusting its various parameters:

Filtering – the Modulation module is provided with variable-frequency hi-pass

and lo-pass shelving lters which may be used to select the band of frequencies that the Modulation will apply to. The lo-pass lter turnover frequency is adjusted with the LS Frequency control, which has a range of 20 to 200 Hz, with a default value of 100 Hz. The LS Gain control has a range of ±18 dB. Similarly, the HS controls affect the higher frequencies; HS Frequency has a range of 1.5 to 15 kHz with a default value of 6.3 kHz; the HS Gain range is also ±18 dB.

Modulation – the Modulation rate and Intensity controls adjust the frequency

and amount of modulation respectively. The controls’ ranges are in arbitrary units, from 50 to 200, with default values of 100.

Sends – the Send Reverb and Send Delay controls send the Modulation module’s output to the Reverb and Delay modules respectively.

Modulation output – the output level to the FX return channel from the Modulation module is adjusted with the Modul Out control. A Modul Pan control is also provided.

Module 2 - Delay

The Delay module is an audio delay line congured specically for musical use.

The module can generate single or multiple echoes at time intervals which may

specied in terms of BPM, and can be set by the user using a Tap Tempo feature. Six delay presets are provided, which may selected with the Preset control:

One Echo 1/4

Two Echo 1/8 Three Echo 1/16 Three Echo 1/16 Delayed Four Echo 1/16 One Echo 1/4 with 4 Reect.

Once a Preset has been selected, the delay effect may be modied as required

by adjusting its various parameters.

Filtering – the Delay module is provided with the same variable-frequency hi-pass

and lo-pass shelving lters as the Modulation module. The LS Frequency, LS Gain, HS Frequency and HS Gain controls have the same functions, parameter

ranges and default values.

Delay time - may be set as a BPM value, using the Tempo control (range 40 to 240 BPM) in conjunction with the Factor control. The Factor control has a

range of 0 to 13 (arbitrary units), with a default value of 8. With Factor set to 8,

the Delay Time (displayed below the Factor control) is based on one repeat per

beat; i.e., with a BPM of 120 and Factor set to 8, the delay time will be 500 ms. Setting Factor to 9 doubles the delay time to 1 s; setting it to 7 halves it to 250 ms.

The maximum delay available from the Delay Module is 2 s.

Revision 1 2012-13CDC FOUR

The table below summarises the relationship between Factor and Delay Time:

FACTOR RATIO TO BPM

1 1/24

2 1/16

3 1/12

4 1/8

5 1/6

6 1/4

7 1/2

8 Equivalent to BPM

9 x 2

10 x 3

11 x 4

12 x 5

13 x 6

Alternatively, a delay time may be set directly by adjusting the BPM and Factor controls while observing the Delay Time display. Factor will operate as a “coarse”

delay time control, while BPM will act as a “ne” control.

Additionally, the output of the delay line may be fed back to its input with the

Feedback control to create multiple echoes with decaying amplitude.

Tap Tempo – Softkey 1 may be used to input a BPM value by tapping the button;

a minimum of three taps is required. The tempo of the taps will then dene the

delay time.

Sends – the Send Reverb control sends the Delay module’s output to the Reverb module.

Module output – the output level of the Delay module is adjusted with the Delay

Out control. A Delay Pan control is also provided.

Module 3 – Reverb

The Reverb Module offers six basic room/plate simulations, which may be

selected with the Preset control:

Hall Bright – a large space

Hall Warm – as Hall Bright, but with less hard surfaces Room Bright – a small space Room Warm – as Room Bright, but with less hard surfaces

Plate Bright – simulation of a traditional echo plate

Plate Warm – as Plate Bright, but with reduced HF reections

Once a Preset has been selected, the reverberation may be modied as required

by adjusting its various parameters.

Filtering – the Reverb module is provided with the same variable-frequency

hi-pass and lo-pass shelving lters as the Modulation and Delay modules. The

Revision 1 2012-13 CDC FOUR

LS Frequency, LS Gain, HS Frequency and HS Gain controls have the same functions, parameter ranges and default values.

Reverb – the Reverb Time parameter sets the basic “size” of the space being simulated, i.e., its RT60 value. The range of available reverb times is preset-

dependent:

PRESET MIN. MAX DEFAULT

Hall Bright

0.8 s 12.0 s 1.6 s

Hall Warm

Room Bright

0.4 s 8.0 s 0.8 s

Room Warm

Plate Bright

0.4 s 6.0 s 0.6 s

Plate Warm

Module output – the output level of the Reverb module is adjusted with the Reverb Out control.

Revision 1 2012-13CDC FOUR

System

The System page provides controls for the CDC FOUR’s oscillator, talkback routing, monitor control functions and Solo system control. The page is divided in four Modules, plus an area on the right for PFL and AFL metering. Most of the controls on these pages have no hardware equivalents, and are selected and

adjusted by using the cursor keys and the ADJUST control.

Oscillator

The CDC FOUR’s line-up oscillator can generate a sine wave, white noise or pink noise for system test or alignment, or for room equalisation purposes.

The oscillator is enabled by pressing Softkey 1 (OSC On/Off). The Type button selects the oscillator output signal – Sine, White (Noise) or Pink (Noise). When

Sine is selected, a Freq control becomes available; in this mode, the oscillator has a range from 10 Hz to 10 kHz. The Oscillator output level is adjusted with the

OSC Level control.

The routing buttons allow the oscillator signal to be routed to any combination of:

L & R – Stereo master buss 1 to 4 – Groups 1 to 4 A1 to A8 – Aux busses 1 to 8

Revision 1 2012-13 CDC FOUR

Talkback

A dynamic microphone or talkback headset mic may be connected to the TALKBACK connector on the rear panel. Talkback mic level is adjusted with the TALKBACK rotary control at the top right of the mixer control surface, or the corresponding virtual TB Level control in the Talkback module.

The routing buttons allow talkback to be routed to any combination of:

L & R – Stereo master buss 1 to 4 – Groups 1 to 4 A1 to A8 – Aux busses 1 to 8

Thus the engineer may speak to the FOH output, individual monitor speakers (when the Aux busses are being used for artist foldback) or to the Group outputs, which may be in use to feed different parts of the stage or auditorium, or a recorder.

The microphone is made active when the TALK button is pressed. The TALK

TALK

button is momentary, and thus must be held down while speaking.

ADJUST

TALK BACK

60 0

PHONES

MONITOR

SUM M

Phones/Monitor

A detailed block diagram of the Phones/Monitor section may be found in the Appendix on page 79.

The CDC FOUR’s monitoring system allows for the connection of either (or both)

headphones or a stereo power amplier and a pair of monitor loudspeakers. The monitor system will carry the Stereo Master output signal, unless a SOLO button

is pressed somewhere on the mixer, in which case either a mono PFL or a stereo

AFL signal from the channel in question will be heard instead.

A standard 3-pole ¼” headphones jack socket is provided at the front of the mixer,

under the fader block. The rear panel provides three ¼” jacks for connection of an external stereo (MON L and MON R) or a mono (MON M) power amplier (useful for an engineer’s local wedge monitor). The front panel headphone socket and the rear panel monitor outputs have their own level controls and may be used simultaneously.

The headphone volume may be adjusted with the rotary PHONES control, or its

virtual equivalent, Phones Level. The headphone output may be muted with the M button below the level control or on-screen.

The separate monitor output level is adjusted with the rotary MONITOR control, or its virtual equivalent, Monitor Level. The monitor output may be muted with

the M button below the level control or on-screen.

The stereo monitor outputs may be summed to mono with either the SUM button, or the Mono on-screen button.

SOLO LOGIC

HOLD SIP

CLEAR

Solo control

The CDC FOUR’s solo system is entirely conventional in operation and follows the long-established practices implemented in CADAC analogue consoles. The solo system allows an engineer to monitor any of the various inputs or outputs

(individually or in combination) on headphones or loudspeakers, without otherwise altering any signal ows through the mixer.

Any channel in the currently selected Layer may be routed to the solo system by pressing the SOLO button above its fader. Alternatively, the channel currently

Revision 1 2012-13CDC FOUR

assigned to the CAM may be soloed with the CAM’s SOLO button, or the on- screen Solo button using screen navigation in the normal manner.

The action of the SOLO buttons in combination may be controlled with the HOLD button. When HOLD is not selected, the SOLO buttons are interlocking, and pressing a second SOLO button while one is already active will deselect the rst; only one channel may be soloed at a time.

With HOLD selected, the SOLO buttons become latching and remain selected when pressed until a second press deselects it. Additional channels may be soloed simultaneously, allowing the monitoring of multiple channels. The CLEAR button may be used to deselect all SOLO buttons currently active with a single button press.

Softkey 6 (Hold) is the on-screen equivalent of the hardware HOLD button. Softkey 7 (Clear) is the on-screen equivalent of the hardware CLEAR button.

PFL and AFL

The on-screen Solo module allows the Solo system to be congured to suit individual requirements. The SOLO buttons in mic/line channels, stereo channels, Aux channels and Groups may be individually selected to operate in PFL (mono)

or AFL (stereo) mode, with the on-screen Channels, St Channels, Auxes and Groups buttons respectively.

Channels soloed in PFL mode will route the pre-fade signal to the solo system,

thus the fader position and mute button will not affect the signal being monitored.

The PFL signal is, however, post all DSP processing, so the effect of EQ, dynamics

and delay can be checked. If stereo channels or the FX channels are solo’d in

PFL mode, a mono sum of the left and right legs is heard.

Channels soloed in AFL mode will route the post-fade, post-panpot signal to the solo system; thus stereo channels will be heard correctly in stereo, and a mono

signal will be heard in its correct position in the stereo image. Fader and mute will affect the solo signal.

When a Group is soloed in AFL mode, the post-fade, post-panpot signal is routed

to the monitor mix.

When an Aux. send is solo’d in either mode, the signal is always mono, but prefade in the case of PFL, and post-fade for AFL.

Revision 1 2012-13 CDC FOUR

TALK BACK

60 0

PHONES

MONITOR

SUM M

Solo system metering and levels

LISTEN

LEVEL

AFL/PFL

MIX

0dB

Stereo Left

AFL/PFL

Stereo Right

MIX

0dB

The solo signals are fed into the mixer’s monitoring system, where they are routed to the rear panel Monitor Outputs (both as stereo and as a mono sum), and the

stereo headphone socket under the front armrest.

The front headphones output has its own volume control (PHONES) and mute (M) button.

LEVEL

LISTEN

LEVEL

DAC

Buffer

10dB

Buffer

10dB

Bal OP

0dB

Bal OP

0dB

MIX

0dB

LEVEL

Bal OP

0dB

MUTE

FRONT PANEL HEADPHONE

MUTE

DIM

14dB

MUTE

DIM

14dB

MUTE

MONITOR OUTPUT LEFT

MONITOR

OUTPUT

RIGHT

MONITOR

OUTPUT

MONO

SOLO LOGIC

HOLD SIP

CLEAR

Signals solo’d in PFL mode will generally be at a higher level than those solo’d in

AFL mode, so separate trim adjustments are also provided for the AFL and PFL systems. These are on-screen controls, and can be found in the Solo module of

the SYSTEM screen page.

SIP mode

The PFL and AFL modes described above are only monitoring modes, and do not alter any other signal routings through the mixer. They are non-destructive,

and can be used safely during performance or recording without endangering any other outputs from the mixer.

A further solo mode, SIP (Solo-in-Place) is available which is destructive. This

mode is also often referred to as ‘Check Solo’. SIP mode is enabled by pressing the SIP button.

In SIP mode, soloing any input channel mutes every other input channel; thus the soloed channel is the only one left feeding the master output (or Group, if applicable). Thus it is ‘truly’ soloed, by virtue of all other signals being removed. This mode is useful when setting up for performance or recording, but should

clearly be used with great caution otherwise!

Solo In Place mode may be selected On or Off by pressing and holding the SIP

button for at least 3 seconds, or clicking or its on-screen equivalent. When Solo

In Place is On, pressing a SOLO button anywhere on the mixer mutes all other channels.

Mono PFL and stereo AFL meters are also provided on the SYSTEM page.

Revision 1 2012-13CDC FOUR

System Settings

Pressing Softkey 8 from the SYSTEM page opens an “engineering” page, which provides information about the rmware version and Ethernet IP address, and

access to further engineering pages via the following softkeys:

Softkey 1 (Fact. Reset) reinitialises the CDC FOUR’s control system. All audio

will be muted during reboot, and all mixer settings will be lost. All parameters will

be reset to their default values.

Softkey 6 (Maintenance) opens the CDC 4 maintenance page allowing mixer and/or scene settings to be saved and recalled from an external USB memory device, and other engineering functions. See page 80 for further details.

Softkey 8 (System) returns to the System page.

Revision 1 2012-13 CDC FOUR

Scene Control

The CDC FOUR incorporates a Scene Memory system. This is a “snapshot”

automation system, and allows every audio-related parameter* on the mixer to be saved as a Scene, named, and subsequently recalled. A Scene may typically include channels being muted and unmuted, levels being changed, and FX sends being enabled, but may extend to any mixer function, such as EQ and dynamics adjustments, routing, FX parameter changes, etc. Up to 999 Scenes may be

saved in this way.

The Scene Memory feature is extremely useful in theatre production work, as entire sound congurations may be set up and optimised in rehearsal, and then saved. During performance, the engineer merely has to step through the

consecutive scenes at the appropriate cue to reset the entire mixer to the correct settings.

* An important exception is the position of the Stereo Master fader; being non-automated, this

remains manual at all times.

Current Scene

An important aspect of the Scene Memory system is that the current status of

the mixer at all times – i.e., the settings of all mixer controls - is constantly being written into a single memory location, referred to as the Current Scene. This is a non-volatile memory, and during the mixer’s boot procedure, the contents of

the Current Scene are recalled. This means that if the mixer suffers a temporary

power failure, its last-known state will be automatically reinstated in all respects

when power returns.

When a Scene is saved, the contents of Current Scene is copied into the selected

Scene Memory.

Pressing the SCENE button adjacent to the screen opens the Scene page:

The scenes which have been saved in the mixer’s internal Scene Memory are displayed in tabular form.

Revision 1 2012-13CDC FOUR

Default Scene

Initially, the only scene in the list is Default. This scene is constant, and cannot be deleted, altered or over-written. Recalling this scene will return the entire mixer to a factory default state, with all channel parameters effectively “reset”. This function is useful when resetting the mixer for a new project, but should be used

with caution otherwise!

Insert a Scene

New Scenes may be added to the Scene list by pressing Softkey 1 (Insert). This copies the contents of the Current Scene memory (see above) into a new Scene in the list. This Scene will be named NEW_SCENE, but may be subsequently renamed (see below).

Renaming Scenes:

To rename a Scene, move the red box to the Scene name in the second column (Name) – e.g., NEW_SCENE. Press ENTER, and a pop-up list will appear,

enabling the Scene name to be changed. Press Softkey 5 (Reset Name) to clear

the eld. Use the ADJUST knob to scroll to the rst character of the new name

from the pop-up list and then press the RIGHT cursor key and repeat. Continue this process until all the characters have been entered as required. Note that

both upper and lower case letters, numbers and other characters are available; a

space character can be found after the upper case letters.

Overwriting Scenes:

To save the mixer’s current settings into an existing Scene, select the required Scene by moving the red box in the displayed list, and press either the SAVE key,

or Softkey 4 (Save). This will over-write the existing Scene.

Recalling Scenes:

CONTROL

DEL RCL SVE COPY PASTE

ENTER

To recall a previously saved scene, use the ADJUST control to move the red box to the required scene in the Scene List (any column), and press either RCL or

Softkey 3 (Recall). This will replace the mixer’s current settings with those from the memory. Any channel level differences in the currently-selected layer will be implemented by movements of the motorised faders.

The sequence of scenes making up the Scene list may be stepped through one at a time by pressing the green N button (Next). At any time, the previous scene in the list may be recalled by pressing the red P button (Previous).

Deleting scenes

A Scene may be deleted from the Scene list by selecting, and pressing either the

DEL button or Softkey 2 (Delete).

Shortcut Scene Recall

User keys U1 to U4 may be assigned as shortcut triggers, which will recall any Scene in the list, removing the necessity to scroll through the list. To assign a Scene to one of the User keys, move the red box to Column 3 (Action) for the required Scene, and press ENTER. Scroll to one of the four User keys in the

Revision 1 2012-13 CDC FOUR

displayed pop-up list (USR 1 to USR 4), and press ENTER again.

If a User Key previously had a Scene assigned to it, that assignment will be cancelled, and the key will now recall the new Scene.

MIDI commands

Column 4 in the list – Event – is not currently implemented.

Revision 1 2012-13CDC FOUR

GRAPHIC EQ

1-16

BANDS

17-32

6/12

Other mixer functions

Graphic Equaliser

The CDC FOUR is equipped with a stereo 32-band graphic equaliser in the main

output signal path. It is pre-fade and pre-dynamics, but post the main output

channel’s standard parametric EQ.

The equaliser settings are controlled by the channel faders, and effectively constitute a sixth control Layer. As there are only 16 faders, the audio frequency band is split into two, and the faders used to control either the sixteen frequencies below 1 kHz, or above I kHz, respectively.

A graphical representation of the equaliser may be obtained by pressing Softkey 6 (GEQ) from the Master Sel screen page. Pressing Softkey 8 (Master Sel) from

this page will return to the previous page.

Control of the graphic equaliser is assigned to the faders by pressing the IN button and one of the 1-16 or 17-32 buttons. If the equaliser has not already been

placed in circuit and adjusted, the 16 motorised faders will jump to their mid-

+6 (or 12) dB

+6 (or 12dB)

position; otherwise, they will assume positions corresponding to the EQ curve

previously set. Note that Fader 16 has no function when 17-32 is selected.

Pressing any Layer Select button will revert the faders to control of another layer,

but the graphic equaliser’s settings will remain applied to the main output.

The equaliser can cut or boost bands of frequencies (centred on the ISO standard

frequencies) by either 6 dB or 12 dB, according to the setting of the 6/12 button.

When the button is lit, 12 dB of cut/boost is selected.

50 60

-6 (or 12) dB

Revision 1 2012-13 CDC FOUR

∞

ST 1 GP 1

The centre frequency of the band which each fader controls is as follows:

Fader 1-16 17-32

1 20 Hz 800 Hz

2 25 Hz 1 kHz

3 31 Hz 1.25 kHz

4 40 Hz 1.6 kHz

5 50 Hz 2 kHz

6 63 Hz 2.5 kHz

7 80 Hz 3.15 kHz

8 100 Hz 4 kHz

9 125 Hz 5 kHz

10 160 Hz 6.3 kHz

11 200 Hz 8 kHz

12 250 Hz 10 kHz

13 315 Hz 12.5 kHz

14 400 Hz 16 kHz

15 500 Hz 20 kHz

16 630 Hz (not used)

Note that pressing Softkey 5 (Flat) from the Graphic Equalizer page will remove

the EQ curve and atten the frequency response.

USB port

The Type ‘A’ USB port on the top panel is for the connection of a USB memory device or USB QWERTY keyboard.

A memory device connected here enable console congurations and scene data

to be backed-up and restored. See “Maintenance page” on page 80.

Ethernet port

Used specically for updating the CDC FOUR’s operating system when software

updates are available. See “Maintenance page” on page 80.

MIDI

The CDC FOUR is equipped with a standard MIDI interface, consisting of three rear panel 5-pin DIN sockets: MIDI, IN, OUT and THRU.

The MIDI interface will be implemented in a future software release.

Revision 1 2012-13CDC FOUR

User buttons (U1 – U4)

ADJUST

TALK

Four programmable soft keys are provided for the operator’s use. These are U1 to U4, to the right of the TFT screen.

The User buttons can be programmed from the Scene page. They allow immediate Scene recall without the necessity of using the Scene page. See “Shortcut Scene Recall” on page 68.

Revision 1 2012-13 CDC FOUR

Technical Specication

Channels 32 (16 mono 8 stereo)

Auxiliaries 8 mono (Switchable pre/post fader) + 2 FX (Switchable pre/post fader)

Sub groups 4 mono, route and pan to Main LR

Input impedance 1k2 ohm mic input on XLR of combi connector

Equivalent Input Noise Better than 128 dB

Input impedance 10k ohm electronically balanced on jack of combi connector

Nominal input level -21 dBFS (0 dBu)

Max. input level 0 dBFS (+21 dBu) balanced -11 dBFS unbalanced (+ 10 dBu)

Max. output level +21 dBu (0 dBFS)

CMRR -70 dB (50 Hz – 10 kHz)

Signal to noise -100 dB

Dynamic range 114 dB A weighted

THD -100 dB

Frequency response 20 Hz to 35 kHz ± 0.5 dB

Crosstalk Better than -80 dB at 10 kHz

Phase response ≤10o @ 20 Hz

ADC 24 bit, 96 kHz

DAC 24 bit, 96 kHz

Internal 40 bit oating point

Revision 1 2012-13CDC FOUR

Appendix

Input Channel Block Diagram

0dB

OUTPUT

Bal OP

DIRECT

6-24dB/Oct

See design brief

for specs

Input channel - INPUT 1 shown

(FEMALE

XLR)

MIC

48v ON

HPF IN

DYNAMICS

48v

GAIN

Buffer

0dB

Buffer

0dB

20dB

PAD

10-60dB

MIC

ADC

14-400Hz

HPF

Limiter

DYNAMICS

Delay

Gate

Compressor

20-200Hz

SHELF SHELF

60-600Hz 400-4kHz

1k5-15kHz

EQ IN

Buffer

0dB

10dB

Buffer

PAN IN

MUTE

PAN

Buffer

4.5dB

AUX PRE

LEVEL

FX 2

AUX 8

FX 1

AUX PRE

LEVEL

GROUP 4

AUX 1

GROUP 2

GROUP 3

GROUP 1

4.5dB

STEREO

FADER

SIG

AS PER J-TYPE CONSOLE

PFL & AFL

DYNAMICS

POST EQ

METER POST

12dB

18dB

0dB

6dB

3dB

24dB

PFL/AFL HOLD/CLEAR SYSTEM

METER

12dB

6dB

PFL

AFL L AFL R

GROUP 1 GROUP 2 GROUP 3 GROUP 4

FX 1 FX 2

AUX 1 AUX 2 AUX 3 AUX 4 AUX 5 AUX 6 AUX 7 AUX 8

STEREO L STEREO R

Revision 1 2012-13 CDC FOUR

Stereo Inputs block diagram

Stereo Input Channel

6-24dB/Oct

See design brief

for specs

SHELF SHELF

RIGHT

INPUT

20dB

PAD

Bal IP

0dB

ADC

14-400Hz

Limiter

Delay

Gate

Compressor

20-200Hz

60-600Hz 400-4kHz

1k5-15kHz

HPF

DYNAMICS

See design brief

for specs

6-24dB/Oct

SHELF SHELF

INPUT

LEFT

20dB

PAD

Bal IP

0dB

ADC

14-400Hz

HPF

HPF IN

Limiter

DYNAMICS

Delay

Gate

Compressor

DYNAMICS

20-200Hz

60-600Hz 400-4kHz

1k5-15kHz

POST EQ

EQ IN

Buffer

0dB

10dB

Buffer

MIX

0dB

MUTE

AUX PRE

LEVEL

GROUP 2

AUX 8

FX 2

FX 1

AUX 1

GROUP 1

PAN IN

GROUP 2

GROUP 1

STEREO

Buffer

0dB

10dB

Buffer

MIX

0dB

METER POST

FADER

BAL

Buffer

4.5dB

PFL/AFL HOLD/CLEAR SYSTEM

AS PER J-TYPE CONSOLE

PFL & AFL

METER

12dB

18dB

6dB

0dB

6dB

3dB

SIG

24dB

METER

12dB

18dB

6dB

0dB

6dB

3dB

SIG

24dB

PFL

AFL L AFL R

GROUP 1 GROUP 2 GROUP 3 GROUP 4

FX 1 FX 2

AUX 1 AUX 2 AUX 3 AUX 4 AUX 5 AUX 6 AUX 7 AUX 8

STEREO L STEREO R

Revision 1 2012-13CDC FOUR

Groups block diagram

PFL

AFL L AFL R

GROUP 1 GROUP 2 GROUP 3 GROUP 4

FX 1 FX 2

AUX 1 AUX 2 AUX 3 AUX 4 AUX 5 AUX 6 AUX 7 AUX 8

STEREO L STEREO R

MIX

0dB

20-200Hz

SHELF SHELF

60-600Hz 400-4kHz

1k5-15kHz

EQ IN

DYNAMICS PRE EQ

Limiter

DYNAMICS

Delay

Gate

Compressor

See design brief

for specs

DYNAMICS

MUTE

METER

12dB

18dB

6dB

0dB

6dB

3dB

SIG

24dB

PFL & AFL

10dB

Buffer

PAN

Buffer

4.5dB

STEREO

DAC

Bal OP

0dB

MUTE

Group Output

GROUP 1

OUTPUT

Revision 1 2012-13 CDC FOUR

Aux outputs block diagram

PFL

AFL L AFL R

GROUP 1 GROUP 2 GROUP 3 GROUP 4

FX 1 FX 2

AUX 1 AUX 2 AUX 3 AUX 4 AUX 5 AUX 6 AUX 7 AUX 8

STEREO L STEREO R

MIX

0dB

SHELF SHELF

See design brief

for specs

PFL & AFL

20-200Hz

60-600Hz 400-4kHz

1k5-15kHz

EQ IN

Limiter

DYNAMICS

Delay

Gate

Compressor

DYNAMICS

MUTE

METER

12dB

18dB

6dB

0dB

6dB

3dB

SIG

24dB

10dB

Buffer

DAC

Bal OP

0dB

MUTE

OUTPUT

AUX 1

Aux Output

Revision 1 2012-13CDC FOUR

Stereo master block diagram

PFL

AFL L AFL R

GROUP 1 GROUP 2 GROUP 3 GROUP 4

FX 1 FX 2

AUX 1 AUX 2 AUX 3 AUX 4 AUX 5 AUX 6 AUX 7 AUX 8

STEREO L STEREO R

SHELF SHELF

See design brief

for specs

PFL & AFL

SHELF SHELF

See design brief

for specs

MIX

0dB

20-200Hz

60-600Hz 400-4kHz

1k5-15kHz

EQ IN

DYNAMICS PRE EQ

Limiter

DYNAMICS

Delay

Gate

Compressor

DYNAMICS

METER

12dB

18dB

6dB

0dB

6dB

3dB

SIG

24dB

METER

12dB

18dB

6dB

0dB

6dB

3dB

SIG

24dB

10dB

Buffer

MIX

0dB

20-200Hz

60-600Hz 400-4kHz

1k5-15kHz

EQ IN

Limiter

DYNAMICS

Delay

Gate

Compressor

DYNAMICS

10dB

Buffer

DAC

MIX

0dB

LEVEL

Bal OP

0dB

MUTE

MASTER

OUTPUT

MONO

Bal OP

0dB

14dB

DIM

MUTE

MASTER

OUTPUT

RIGHT

DAC

Bal OP

0dB

14dB

DIM

MUTE

MASTER

OUTPUT

LEFT

Bal OP

0dB

OUTPUT

RIGHT

TAPE

Bal OP

0dB

MUTE

Stereo Output

OUTPUT

RIGHT

TAPE

Revision 1 2012-13 CDC FOUR

Phones/Monitor block diagram

PFL

AFL L AFL R

GROUP 1 GROUP 2 GROUP 3 GROUP 4

FX 1 FX 2

AUX 1 AUX 2 AUX 3 AUX 4 AUX 5 AUX 6 AUX 7 AUX 8

STEREO L STEREO R

FROM STEREO MASTER

MIX

0dB

SIG

24dB

SIG

24dB

LEVEL

TRIML

AFL

MIX

0dB

LEFT

RIGHT

2 Track Tape Return

STEREO

LEVEL

DAC

STEREO

LISTEN

LEVEL

DAC

STEREO

MIX

0dB

LISTEN

LEVEL

DAC

MIX

0dB

METER

12dB

18dB

6dB

0dB

6dB

3dB

METER

12dB

18dB

6dB

0dB

6dB

3dB

METER

12dB

18dB

6dB

0dB

6dB

3dB

SIG

24dB

LEVEL

TRIM

PFL

10dB

Buffer

MIX

0dB

LEVEL

Bal OP

0dB

MONITOR

OUTPUT

MONO

Bal OP

0dB

14dB

DIM

MUTE

MONITOR

OUTPUT

RIGHT

Bal OP

0dB

14dB

DIM

MUTE

LEFT

MONITOR

OUTPUT

Buffer

MUTE

MONITOR

OUTPUT

MONO

Revision 1 2012-13CDC FOUR

Maintenance page

CENTRAL CONTROL MODULE

USB

METERS

SCENE

ROUTE

SYSTEM

CHN

NOTE: Selecting the Maintenance page from the System Settings page stops the CDC FOUR’s main operating program and starts a separate software routine.

Audio is muted in Maintenance mode, so this page should not be opened during

performance. Loading the maintenance page takes approx. 20 seconds.

The following options are available from the Maintenance page via the Softkeys:

Softkey 1 (Full Backup): This permits all settings, parameters and rmware in the CDC FOUR to be saved to an external memory device connected to the USB port in the Central Control Module. It effectively creates a full “image” of the console for security purposes.

A full backup creates a zip le cdc4-update.zip in the root folder of the memory device. The size of the le is approx. 2MB.

Softkey 2 (Scene Backup): This allows the current Scene List to be backed up

to external memory. A zip le cdc4-scene.zip is created in the root folder of the memory device. Note – any subsequent Backup will overwrite the previously-

saved le, as the lename is unique.

Softkey 3 (Full Restore): Selecting this option will allow all the CDC FOUR’s settings to be restored in full to a previously-saved state. The Full Restore

procedure looks for a backup zip le on the memory device, and will automatically

restore all settings without further operator action.

Softkey 4 (Scene Restore): This option loads a previously-saved Scene List into

the CDC FOUR, thus allowing the “running order” of a show to be restored.

Softkey 5 (Net Update): Select this option to perform a remote software update. The CDC FOUR will automatically download the latest software directly from Cadac’s support server.

WARNING: Performing a Net Update will delete ALL console settings, including all stored Scenes. Before proceeding with the update procedure it is strongly recommended that either a Full Backup or Scene Backup is performed.

Proceed as follows:

Revision 1 2012-13 CDC FOUR

Ensure that an Ethernet cable with Internet connection is plugged into the CDC FOUR’s rear panel RJ45 socket.

Reboot by power-cycling the mixer, then return to the Maintenance page and select Net Update.

The CDC FOUR will automatically download and install the current version of software.

NOTE: The CDC FOUR will always download and install the latest version of software irrespective of whether it is already installed in the console or not.

Upon completion, the CDC FOUR will display the following message, “Software

successfully updated to the latest version!”

To re-boot the CDC FOUR it is necessary to power-cycle the console twice. After

the rst power-cycle wait until all the LEDs on the console are lit, then perform the

second power-cycle. The console will then boot with the latest version of software installed.

To check which version of software the console is running, press the System button and then the System Settings softkey (Sys.Settings).

If console scenes were backed-up prior to updating the software then restore these into the CDC FOUR by using the Scene Restore function above.

NOTE: It is not possible to return to the CDC FOUR’s normal operating system

from the Maintenance page. To exit this page, please re-boot the console by

power-cycling.

Revision 1 2012-13CDC FOUR

Connecting the CDC FOUR to unbalanced sources and desti-

nations

All inputs and outputs on the CDC FOUR are electronically balanced. Balanced

interconnections to external equipment are recommended, as they will minimise noise pickup, hum problems, and generally use superior quality connectors.

Most current professional audio equipment is equipped with balanced inputs and

outputs, but it may occasionally be necessary to interface the CDC FOUR with

equipment having unbalanced inputs and/or outputs. Cadac’s recommended method of connecting balanced and unbalanced terminations is shown below:

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Revision 1 2012-13 CDC FOUR

Revision 1 2012-13CDC FOUR

Cadac CDC four User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual