Soundcraft SM20 USER GUIDE

SM20 Contents 1

2 SM20 Contents

© Harman International Industries Ltd. 1998

All rights reserved

Parts of the design of this product may be protected by worldwide patents.

Part No. ZM0226

Issue 1

Soundcraft is a trading division of Harman International Industries Ltd.

Information in this manual is subject to change without notice and does not repre-

sent a commitment on the part of the vendor. Soundcraft shall not be liable for

loss or damage whatsoever arising from the use of information or any error con-

tained in this manual.

No part of this manual may be reproduced, stored in a retrieval system, or trans-

mitted, in any form or by any means, electronic, electrical, mechanical, optical,

chemical, including photocopying and recording, for any purpose without the

express written permission of Soundcraft.

It is recommended that all maintenance and service on the product should be car-

ried out by Soundcraft or its authorised agents. Soundcraft cannot accept any lia-

bility whatsoever for any loss or damage caused by service, maintenance or repair

by unauthorised personnel.

Harman International Industries Limited.

Cranborne House,

Cranborne Road,

Cranborne Industrial Estate,

Potters Bar,

Herts.,

EN6 3JN

UK.

Tel: [phone]

Fax: [phone]

SM20 Contents i

SSMM2200

CCoonntteennttss

1. Introduction 1.1

Introduction 1.2

Warranty 1.2

2. Installation 2.1

Dimensions and Configurations 2.2

Precautions and Safety Instructions 2.3

Mains Installation 2.4

Connections 2.6

Jumper Options 2.7

Block Diagrams 3.1

Input Module 3.2

Output Module 3.3

Master Module 3.4

Functional Description 4.1

Input Module 4.2

Output Module 4.5

Master Module 4.8

Specifications 5.1

ii SM20 Contents

SM20 Introduction 1.1

SSMM2200

IInnttrroodduuccttiioonn

1

1.2 SM20 Introduction

IInnttrroodduuccttiioonn

Congratulations on purchasing a Soundcraft console.

The SM20 is a dedicated stage monitor console, designed to take account of the

trend towards the use of in-ear monitoring systems, and draws on elements from

the respected range of Soundcraft SM consoles.

SSyysstteemm OOvveerrvviieeww

l 32, 40, 48 and 56-module frames

l Mono input with wide-range, low-noise input pre-amp

l Mic split output on each channel

l Combination of mono and stereo sends giving from 20 mono sends to

7 stereo and 6 mono sends, with individual pre/post fader switching

l 8 Mute groups

l Optional VU Meterbridge

l Balanced audio inputs and outputs throughout, on XLRs

l MIDI control of BSS Varicurve Equaliser

PPoowweerr SSuuppppllyy

l The SM20 uses the CPS800 Power Supply.

SM20 Introduction 1.3

WWaarrrraannttyy

1 Soundcraft is a trading division of Harman International Industries Ltd .

End User means the person who first puts the equipment into regular

operation.

Dealer means the person other than Soundcraft (if any) from whom the

End User purchased the Equipment, provided such a person is authorised

for this purpose by Soundcraft or its accredited Distributor.

Equipment means the equipment supplied with this manual.

2 If within the period of twelve months from the date of delivery of the

Equipment to the End User it shall prove defective by reason only of faulty

materials and/or workmanship to such an extent that the effectiveness

and/or usability thereof is materially affected the Equipment or the defec-

tive component should be returned to the Dealer or to Soundcraft and

subject to the following conditions the Dealer or Soundcraft will repair or

replace the defective components. Any components replaced will become

the property of Soundcraft.

3 Any Equipment or component returned will be at the risk of the End User

whilst in transit (both to and from the Dealer or Soundcraft) and postage

must be prepaid.

4 This warranty shall only be available if:

a) the Equipment has been properly installed in accordance with instruc-

tions contained in Soundcrafts manual; and

b) the End User has notified Soundcraft or the Dealer within 14 days of the

defect appearing; and

c) no persons other than authorised representatives of Soundcraft or the

Dealer have effected any replacement of parts maintenance adjustments or

repairs to the Equipment; and

d) the End User has used the Equipment only for such purposes as

Soundcraft recommends, with only such operating supplies as meet

Soundcrafts specifications and otherwise in all respects in accordance

Soundcrafts recommendations.

5 Defects arising as a result of the following are not covered by this

Warranty: faulty or negligent handling, chemical or electro-chemical or

electrical influences, accidental damage, Acts of God, neglect, deficiency in

electrical power, air-conditioning or humidity control.

6 The benefit of this Warranty may not be assigned by the End User.

7 End Users who are consumers should note their rights under this Warranty

are in addition to and do not affect any other rights to which they may be

entitled against the seller of the Equipment.

1.4 SM20 Introduction

SM20 Installation 2.1

SSMM2200

IInnssttaallllaattiioonn

2

2.2 SM20 Installation

DDiimmeennssiioonnss aanndd CCoonnffiigguurraattiioonnss

Mono Input

Output

Master

48ch 56ch

795.80 (31.33")

722.80 (28.46")

373.40 (14.70")

277.88 (10.94")

25.0 (1.00")

125.70

(4.95")

32ch frame
40ch frame
48ch frame
56ch frame

Overall Width

1366mm (53.8“)
1620mm (63.78“)
1874mm (73.78")
2128mm (83.78")

Console

40ch

SM20 Installation 2.3

PPrreeccaauuttiioonnss aanndd SSaaffeettyy IInnssttrruuccttiioonnss

GGeenneerraall PPrreeccaauuttiioonnss

Avoid storing or using the mixing console in conditions of excessive heat or cold,

or in positions where it is likely to be subject to vibration, dust or moisture. Do

not use any liquids to clean the fascia of the unit: a soft dry brush is ideal. Use only

water or ethyl alcohol to clean the trim and scribble strips. Other solvents may

cause damage to paint or plastic parts.

Avoid using the console close to strong sources of electromagnetic radiation (e.g.

video monitors, high-power electric cabling): this may cause degradation of the

audio quality due to induced voltages in connecting leads and chassis. For the

same reason, always site the power supply away from the unit.

Caution!

In all cases, refer servicing to qualified personnel.

HHaannddlliinngg aanndd TTrraannssppoorrtt

The console is supplied in a strong carton or crate. If it is necessary to move it any

distance after installation it is recommended that this packing is used to protect it.

Be sure to disconnect all cabling before moving. If the console is to be regularly

moved we recommend that it is installed in a foamlined flightcase. At all times

avoid applying excessive force to any knobs, switches or connectors.

PPoowweerr SSuupppplliieess && ccaabblleess

Always use the power supply and cable supplied with the mixer: the use of alter-

native supplies may cause damage and voids the warranty; the extension of power

cables may result in malfunction of the mixing console.

Warning!

Always switch the power supply off before connecting or disconnecting

the mixer power cable, removing or installing modules, and servicing. In

the event of an electrical storm, or large mains voltage fluctuations,

immediately switch off the PSU and unplug from the mains.

Warning!

Use only the Soundcraft CPS800 or CPS2000 power supply with your

SM20 console.

SSiiggnnaall LLeevveellss

It is important to supply the correct input levels to the console, otherwise signal to

noise ratio or distortion performance may be degraded; and in extreme cases,

damage to the internal circuitry may result. Likewise, on all balanced inputs avoid

sources with large commonmode DC, AC or RF voltages, as these will reduce the

available signal range on the inputs. Note that 0dBu = 0.775V RMS.

2.4 SM20 Installation

MMaaiinnss IInnssttaallllaattiioonn

GGeenneerraall WWiirriinngg PPrroocceedduurreess

To take full advantage of the excellent signal to noise ratio and low distortion of

Soundcraft consoles care must be taken to ensure that incorrect installation and

wiring does not degrade the performance of the desk. Hum, buzz, instability and

Radio Frequency interference can usually be traced to earth loops and inferior earth-

ing systems. In some areas, especially heavily industrial areas, the incoming mains

earth will not be adequate and a separate technical earth for all the audio equipment

must be supplied. However, check with your local electricity supply company to

ensure that safety regulations are not infringed or negated.

The successful, hum free, installation of a system requires forethought, and the estab-

lishment of a set of ground rules, which must be consistently adhered to at all stages

of installation.

IInniittiiaall WWiirriinngg CCoonnssiiddeerraattiioonnss

For optimum performance, it is essential for the earthing system to be clean and noise

free, as all signals are referenced to this earth. A central point should be decided on

for the main earth point system, and all earths should be `star fed from this point. It

is common electrical practice to daisy chain the earths to all electrical outlets but this

method is unsuitable for audio installations. The preferred method is to run an indi-

vidual earth wire from each outlet, back to the system star point to provide a safety

earth screen reference for each piece of equipment.

A separate earth wire should also be run from each equipment rack and area, to the

star point. This may or may not be used depending on circumstances, but it is easier

to install in the first place, than later when problems arise.

The location of the star point should be a convenient, easily accessible place, prefer-

ably at the rear of the console or in the main equipment rack.

Install separate clean and dirty mains outlets, wired individually back to the incom-

ing mains distribution box. Use the clean supply for all audio equipment and the

dirty supply for all lighting, etc. Never mix the two systems.

If necessary, to provide sufficient isolation from mains borne interference, install an

isolating transformer. This should be provided with a Faraday Shield which must be

connected with earth.

Never locate the incoming mains distribution box near audio equipment, especially

tape recorders, which are very sensitive to electro-magnetic fields.

Ensure that all equipment racks are connected to earth, via a separate wire back to

the star point.

Equipment which has unbalanced inputs and outputs may need to be isolated from the

rack to prevent earth loops.

AAuuddiioo WWiirriinngg

Having provided all equipment with power and earthing connections, consideration

must be given to the method of providing audio interconnection and adequate screen-

ing of those interconnections. This must be done in a logical sequence to avoid prob-

lems and assist in the localisation of problem equipment.

l Connect the Monitor system to the console and check for any hum, buzz, or

RFI. Only when you are satisfied with the quietness of the console and the

monitor system should you proceed with the next step.

l Connect stereo tape recorders, echo and foldback sends one at a time, check-

ing and isolating any connection which degrades performance.

l Connect all other peripheral devices.

SM20 Installation 2.5

l Connect all microphone lines.

By following this sequence much time and future trouble will be saved, and the result

will be a quiet, stable system.

SShhiieellddiinngg

Audio equipment is supplied with a variety of input and output configurations, which

must be taken into consideration when deciding where the screen connections should

be made. There are three sources of unwanted signal being impressed on the screen,

which are as follows:

l Extraneous electrostatic or electromagnetic fields.

l Noise and interference on the earth line.

l Capacitive coupling between the screen and signal wires.

To minimise the adverse affects of the unwanted coupling to the signal wires, it is

important that the screen is connected at one end only, i.e. the screen must not carry

any signal current. Any signal on the wires within the screen will be capacitively cou-

pled to the screen. This current will ultimately be returned to the source of the sig-

nal, either directly, if the screen is connected at the signal source end, or indirectly via

the earthing system, if the signal is connected at the signal destination end. The indi-

rect connection will cause an increase in high frequency cross-talk, and should be

avoided wherever possible.

Therefore, in general, always connect the shield only at the signal source end. In high

RF areas, the screen can also be connected to earth via a 0.01

µF capacitor. This will

present a short circuit at RF frequencies, thus lowering the effective shield impedance

to ground. However, at low audio frequencies the reactance of the capacitor will be

sufficiently high not to cause an earth loop problem.

PPooiinnttss ttoo RReemmeemmbbeerr

l In all cases, use good quality twin screened audio cable. Check for instability at

the output.

l Always connect both conductors at both ends, and ensure that the screen is

only connected at one end.

l Do not disconnect the mains earth from each piece of equipment. This is

needed to provide both safety and screen returns to the system star point.

l Equipment which has balanced inputs and outputs may need to be electrically

isolated from the equipment rack and/or other equipment, to avoid earth

loops.

It is important to remember that all equipment which is connected to the mains is a

potential source of hum and interference and may radiate both electrostatic or elec-

tromagnetic radiation. In addition, the mains will also act as a carrier for many forms

of RF interference generated by electric motors, airconditioning units, thyristor light

dimmers etc. Unless the earth system is clean, all attempts to improve hum noise lev-

els will be futile. In extreme cases there will be no alternative but to provide a com-

pletely separate and independant technical earth to replace the incoming noisy

earth. However, always consult your local electricity supply authority to ensure that

safety regulations are not being infringed.

2.6 SM20 Installation

CCoonnnneeccttiioonnss

22

11

33

ALL INPUTS ALL OUTPUTS

GROUND (SCREEN)

COLD (OUT OF

PHASE SIGNAL)

HOT

(IN PHASE SIGNAL)

Socket(female)

Plug(male)

3-pole XLR

Audio Connectors

Lamp Connectors

MIDI Connectors

Tip - HOT(IN PHASE SIGNAL)

Ring - COLD(OUT OF PHASE SIGNAL)

Sleeve - GROUND(SCREEN)

Tip - HOT(IN PHASE SIGNAL)

Ring - COLD(OUT OF PHASE SIGNAL)

Sleeve - GROUND(SCREEN)

1

4/

"

Stereo Jack Plug used as balanced Input/Output:

Tip - LEFT SIGNAL

Ring - RIGHT SIGNAL

Sleeve - GROUND(SCREEN)

Pin4=0V

Pins 1 and 3 = +/-12V

1

4/

"

Stereo Jack Plug used for Inserts

1

4

/"Stereo Jack Plug used for Headphones

Not Used

Midi In -

Midi In +

Not Used

Not Used

1

4

2

5

3

MIDI IN

Not Used

Not Used

GND

MIDI Out -

MIDI Out +

MIDI OUT

1

4

2

5

3

SM20 Installation 2.7

JJuummppeerr OOppttiioonnss

IInnppuutt MMoodduullee RRHH BBooaarrdd

J1 Insert Send/Return Fitted = Pre EQ (default)

J2 Insert Send/Return Fitted = Pre EQ (default)

J3 Insert Send/Return Fitted = Pre EQ (default)

J4 Insert Send/Return Fitted = Post EQ

J5 Insert Send/Return Fitted = Post EQ

J6 Insert Send/Return Fitted = Post EQ

J7 Direct Out Fitted = Pre EQ (default)

J8 Direct Out Fitted = Pre Mute

J9 Direct Out Fitted = Post Mute

J10 Direct Out Fitted = Pre EQ, Post Mute

J11 Groups 1-4 Pre Source Fitted = Pre EQ

J12 Groups 1-4 Pre Source Fitted = Pre Mute

J13 Groups 1-4 Pre Source Fitted = Post Mute (default)

J14 Groups 1-4 Pre Source Fitted = Pre EQ/Post Mute

J15 Groups 5-8 Pre Source Fitted = Pre EQ

J16 Groups 5-8 Pre Source Fitted = Pre Mute

J17 Groups 5-8 Pre Source Fitted = Post Mute (default)

J18 Groups 5-8 Pre Source Fitted = Pre EQ/Post Mute

J19 Groups 9-12 Pre Source Fitted = Pre EQ

J20 Groups 9-12 Pre Source Fitted = Pre Mute

J21 Groups 9-12 Pre Source Fitted = Post Mute (default)

J22 Groups 9-12 Pre Source Fitted = Pre EQ/Post Mute

J23 Groups L/R Pre Source Fitted = Pre EQ

J24 Groups L/R Pre Source Fitted = Pre Mute

J25 Groups L/R Pre Source Fitted = Post Mute (default)

J26 Groups L/R Pre Source Fitted = Pre EQ/Post Mute

J27 Direct Out Fitted = Postfade

OOuuttppuutt MMoodduullee

No jumper-selectable options.

MMaasstteerr MMoodduullee CCeennttrree BBooaarrdd

No jumper-selectable options

MMaasstteerr MMoodduullee RRHH BBooaarrdd

J1 Talk to FOH dc signalling 1-2 = disabled

2-3 = enabled (default)

J2 FOH TB In dc signalling 1-2 = enabled (default)

2-3 = disabled

2.8 SM20 Installation

SM20 Block Diagrams 3.1

SSMM2200

BBlloocckk DDiiaaggrraammss

3

3.2 SM20 Block Diagrams

OPTIONAL RELAY

SWITCH TRANSFORMER

BOARD

MULTIPIN

OPTION

INSERT

SEND

INSERT

RETURN

DIRECT

OUTPUT

MULTIPINOPTION

POSTMUTE

POSTMUTE

PRE EQ/POST MUTE

PRE EQ/POST MUTE

PRE EQ/POST MUTE

PRE EQ/POST MUTE

PRE EQ/POST MUTE

PRE EQ/POST MUTE

PRE EQ/POST MUTE

PRE EQ/POST MUTE

POSTFADE

POSTMUTE

POSTMUTE

POSTMUTE

POSTMUTE

POSTMUTE

SEND R

SEND 8B

SEND 7B

SEND 12B

SEND 11B

SEND 10B

SEND 9B

SEND L

SEND 8A

SEND 7A

SEND 6

SEND 5

SEND 12A

PRE

PRE

PRE

GLOBAL STE SWITCHING BUSSES

GLOBAL STE SWITCHING BUSSES

PRE

EQ

PFL

INS

MUTE

SAFE

1

8

MUTE

RNGE

+48V

PRE

PRE

PRE

PRE

PRE

PRE

PRE

PRE

PRE

SEND 11A

SEND 10A

SEND 9A

PREMUTE

PRE_EQ

POST EQ

SHELFSHELF

POSTEQ

PRE_EQ

20-400Hz

+20 PK

+14

+18+5+30-5

-10

-20

-30

INPUT

METER

POST EQ

POSTFADE

PEAK

DETECTOR

HI-PASSFILTER

BELLBELL

FREQFREQ

Q

FREQ

Q

FREQ

CUT/

BOOST

CUT/

BOOST

CUT/

BOOST

CUT/

BOOST

28kHz

28kHz

12kHz

3

12kHz

1.5kHz

3

1.5kHz

480Hz

480Hz

1kHz

1kHz

450Hz

0.5

450Hz

78Hz

0.5

78Hz

LF HFLOW_MID HI_MID

30Hz

30Hz

PFL

LOGIC

PFL DETECT

GLOBAL STE SWITCHING BUSSES

GROUP BUSSES 1-20

PFL BUS

INPUT SOLO CLEAR

SEND 4

SEND 3

SEND 2

SEND 1

L/R

L/R

L/R

L/R

L/R

L/R

L/R

PREMUTE

PREMUTE

PREMUTE

PREMUTE

PREMUTE

PREMUTE

PRE_EQ

PRE_EQ

PRE_EQ

PRE_EQ

PRE_EQ

PRE_EQ

PRE_EQ

POSTED

POSTED

PRE_EQ

MUTE

LOGIC

MUTE BUS

MUTE ASGN

(2 OF 8 SHOWN)

FADER

+10

PREMUTE

PREMUTE

PRE_EQ

POSTFADE

PRE_EQ

POSTFADE

-2dBu GROUND COMP O/P

-2dBu GROUND COMP O/P

-2dBu WITH GROUND COMP SEND

+4dBu WITH EBOS BALANCED SEND

+4dBu BALANCED EBOS

OPTION AVAILABLE

+4dBu BALANCED EBOS

OPTION AVAILABLE

MIC SPLIT

-2dBu TO -70dBu
+10dBu TO -20dBu

INPUT

1

1

2

2

3

3

PIN 1

LIFT

REMOVE LINKS

FOR TX OPTION

+48V

INPUT REAR CONN

SENS

PUSH

Ø

Input Module

SM20 Block Diagrams 3.3

OUT

L

R

STE

STE LINKING

AFL TRIM

AFL

OUT

L

R

SUMMING AMP

GRP 7A(1 OF 6 STEREO SENDS)

FADER

+10

INSERT

AFL

LOGIC

STE LINKING

AFL LOGIC OUT

AFL CLEAR

0dB STE MODE

-6dB MONO MODE

+10

-10

0

LOGIC BUS

LOWER MONO GROUP SHOWN

UPPER MONO GROUP 1 OF 2 SHOWN

GROUPS A AND B CAN BE CONFIGURED AS A STEREO

GRP 7A/8 (1 OF 6 SEND ENABLE LINES)

STE

LOGIC

INSERT

-6dB

+10

SUMMING AMP

GRP 1(1OF6)

AFL

LOGIC

AFL

AFL TRIM

AFL LEFT

AFL RIGHT

GROUP BUS A

GROUP BUS L

GROUP BUSSES

AFL LEFT

AFL RIGHT

GROUP BUS A

GROUP BUS L

GROUP BUSSES

0

+10

-10

AFL LOGIC OUT

AFL CLEAR

FADER

GLOBAL MUTE

MUTE

6dB DIM

6dB DIM

MUTE

MUTE

LOGIC

GLOBAL MUTE

OUTPUT TO DIM

OUTPUT TO DIM

TB/OSC BUS

TB/OSC BUS

TB

TB

EBOS

EBOS

EBOS

EBOS

EXT IN

EXT IN

+10

+10

ON

ON

TO OPTIONALVU OVERBRIDGE

TO OPTIONALVU OVERBRIDGE

GROUP OUTPUT AND

GROUP INSERTREAR CONNS

GROUP OUTPUT AND

GROUP INSERTREAR CONNS

(Tx/MULTIPIN)

GROUP

OUTPUT

GROUP

OUTPUT

+20

+20

-20

-20

-30

-30

+15

+15

-15

-15

+10

+10

-10

-10

+5

+5

-5

-5

0

0

INSERT

RETURN

INSERT

RETURN

INSERT

SEND

INSERT

SEND

EXTERNAL

INPUT

EXTERNAL

INPUT

2

2

2

2

1

1

1

1

3

3

3

3

PUSH

PUSH

MUTE

LOGIC

Ø

Ø

å

å

å

å

Output Module

3.4 SM20 Block Diagrams

SUPPLY

RAIL

SENSE

CIRCUITRY

ALT

WEDGE R

OUTPUT

WEDGE R

OUTPUT

DELAY

LOGIC

MUTE

LOGIC

GROUP MUTE

LOGIC BUS

XLR

LOCATED

ON MASTER

XLRS

LOCATED

ON END CHEEKS

MUTE

ALL

GROUPS

WEDGE L

OUTPUT

ALT

WEDGE L

OUTPUT

PHONES

OUTPUT

PHONES

LEVEL

PHONES

DIM

MONO

LOGIC

MONO

SOURCE

MONO

SOURCE

SOLO

CLR

PFLTRIM0

+10

-10

LPOST FADE

R POST FADE

EXT AFL

RIGHT OUT

EXT AFL

LEFT OUT

EXT PFL

OUT

EXT AFL

RIGHT IN

PFLDETECT

AFLDETECT

AFLLEFT BUS

AFLRIGHT BUS

PFLBUS

EXT AFL

LEFT IN

EXT PFL

IN

I/P PRIORITY

AUTO CANCEL

ENBL

ENBL

SOLO

LOGIC

L

R

&

EXT TB TOPHONES

FADER

FADER

WEDGE DIM

WEDGE DIM

TO OPTIONALVU OVERBRIDGE

TO OPTIONALVU OVERBRIDGE

DIM

20dB

DIM

15dB

DIM

15dB

DIM

20dB

ALT

WEDGE

LEVEL

LAMP

DIMMER

IN

CALL

DETECT

EXTERNAL

INPUT

INSERT

SEND

INSERT

RETURN

GROUP

OUTPUT

1

2

3

EBOS

ON

+10

L/R TO WEDGE

LPOST FADE

R POST FADE

R POST MUTE

MUTE

LOGIC

+10

FADER

INSERT

AFL

LOGIC

STE

LOGIC

OSCILLATOR

OUTPUT

TB/OSC

ON

ON

ON

+10

OSC

LEVEL

FREQ

TB

GAIN

63Hz

-20

FOH

ON

ON

TALKTO

TALKTO

BUSSES

(TB/OSC)

TALKTO

OUTPUTS

(TB/OSC)

TB/OSC

15V CARRIER DETECT

EXT TB TOPHONES

15V

CARRIER ENABLE

WEDGE DIM

PHONES DIM

OUTPUT

TB/OSC DIM

LOGIC BUS

GROUP OUTPUTDIM

TB/OSC BUS

GROUP BUSSES

TALKBACK

LOGIC

1kHz

-50

x10

SRC

OSCILLATOR

TB MIC

ON REAR

FOH TALKBACK

OUTPUT

FOH TALKBACK

INPUT

1

1

1

1

2

2

2

3

3

3

2

3

TB MIC

ON MASTER

PUSH

PUSH

PUSH

PUSH PUSH PUSH

PUSH

PUSH

48V

+48V

PINK NOISE

GENERATOR

OSC TO

OUTPUTS

(TB/OSC)

OSC TO

ALLBUSSES

OSC TO

XLR O/P

1

2

3

STEREO SEND ENABLE

GRP L/R

STE LINKING

LOGIC BUS

STE LINKING

AFLLOGIC OUT

AFLCLEAR

AFL

AFLLEFT

AFLRIGHT

GROUP BUSSES L/R

STE

GRP L

AFLTRIM0

+10

-10

SUMMING

AMP

0dB STE MODE

-6dB MONO MODE

OUT

GLOBALMUTE

ON

MUTE

EBOS

TO OPTIONALVU OVERBRIDGE

TB/OSC BUS

TB

OUTPUT TB DIM

6dB DIM

EXT IN

LITTLITE

BLINK

OSCILLATOR

OUT

CLEAR COM

ALT

WEDGE

LEVEL

ALT

WEDGE

ALT

WEDGE

WEDGE

MONO GROUP 1 OF 2 SHOWN

GROUPS A AND B CAN BE CONFIGURED AS A STEREO PAIR

+20+20

+15+15

+10+10

+5+500-5-5

-10-10

-15

-20

-30

-15

-20

-30

R L

PRE

ON

+10

+10

+10

+10

1

1

1

1

1

1

1

2

2

2

2

2

2

2

3

3

3

3

3

3

3

MUTE MASTERS

MUTE BUS

1

8

+5V

±17V

+48V

Ø

å

å

å

å

å

å

å

å

å

å

å

å

å

å

GROUP OUTPUT AND

GROUP INSERTREAR CONNS

(Tx/MULTIPIN)

Master Module

SM20 Functional Description 4.1

SSMM2200

FFuunnccttiioonnaall DDeessccrriippttiioonn

4

4.2 SM20 Functional Description

IInnppuutt MMoodduullee

1

SSEENNSS ((SSeennssiittiivviittyy))

The SENSitivity Control adjusts the level of the signal which is present on the

Input XLR. The input can handle mic or line level signals up to +30dBu, with the

RANGE switch (see below) selecting high or low sensitivity.

2

4488VV

The 48V switch, when it is depressed, places 48V phantom power on pins 2 & 3 of

the input XLR. An integral LED glows when the phantom power is on.

3

RRNNGGEE ((RRaannggee))

The RNGE (Range) switch selects between an input range of -2dBu to -70dBu

(switch released), and +10dBu to -20dBu (switch pressed and lit), enabling both

mic and line level signals to be handled by a common input stage.

CAUTION: Phantom power should not be switched on when unbalanced sources

are connected to the XLR input.

4

ØØ ((PPhhaassee))

The PHASE switch reverses the phase of the input signal, to compensate for

incorrect wiring or mic placement. The switch is internally illuminated when phase

is reversed.

5

HHPPFF ((HHiigghhppaassss FFiilltteerr))

The HPF Filter control sets the cutoff (-3dB) frequency of the high-pass filter: it is

adjustable between 20Hz and 400Hz, to help reduce stage rumble or popping

from microphones. The control also has a built-in switch to switch the filter out of

circuit when rotated fully anticlockwise.

6

IINNSS ((IInnsseerrtt PPooiinntt))

The Insert Point may be switched in circuit by the INS switch. The insert uses

separate balanced jacks for send and return. It is normally positioned after the

filter and before the equaliser, but can be repositioned using internal jumpers to

be post-EQ if required. The insert is in-circuit when the switch is illuminated.

7

EEQQ

The EQ section comprises four sweepable bands, and the two mid bands are fully

parametric, with adjustable Q. The EQ is enabled when the EQ switch is pressed,

and bypassed when the switch is released. The EQ is active when the EQ switch

is illuminated.

8

HHFF

The HF section is fully sweepable, providing 15dB boost or cut at 1kHz to 20kHz.

The section can be switched to work as either a Shelving control (SHLF switch

pressed) or Bell control (switch released).

9

HHMMFF//LLMMFF

The high and low MID sections comprise a dual concentric control to set the

centre frequency (outer ring) and 15dB of boost or cut (upper knob). The HMF

spans the range 450Hz to 12kHz and the LMF spans the range 70Hz to 1.5kHz.

Each section has an associated Q control, variable from 0.5 to 3.0.

0

LLFF

The LF section is fully sweepable, providing 15dB boost or cut at 30Hz to 480Hz.

The section can be switched to work as either a Shelving control (SHLF switch

pressed) or Bell control (switch released).

RNGE

SM20 Functional Description 4.3

q

MMoonniittoorr SSeennddss 11--66

Sends are provided to the 20 output busses, and are designed to allow a mixture

of mono and stereo sends that will suit typical operational scenarios. The lower 6

sends are configured as full-time mono sends, using single pots. Pressing the PRE

button adjacent to each Send switches the source to pre-fade. The outputs of

these mixes are controlled by the lower bank of 6 output faders in the output

section. The pre-fade source for the sends may be reconfigured to suit individual

requirements - see Jumper options in Chapter 2.

w

MMoonniittoorr SSeennddss 77--1122,, LL//RR

The sends to outputs 7-20 are on dual concentric pots, and each row can be

configured at the touch of a button as either a stereo send with level on the top

knob and pan on the lower, or a pair of mono sends. These mixes are controlled

by the upper bank of 12 faders in the output section, and are labelled 7A and B to

12A and B. Stereo mode is selected by pressing the Global Mode STE button on

the respective output module.

The last pair of sends although marked L and R, is functionally identical to the

other stereo sends and can either be used as a stereo sidefill output, or two mono

sends. The output faders for these sends are located on the master module.

The pre-fade feed for all sends is jumper selectable in four groups, pre or post-EQ

and pre or post-mute, allowing the module to be configured with any combination

of between 20 mono and 6 mono plus 7 stereo sends. The pre-fade source for

the sends may be reconfigured to suit individual requirements - see Jumper

options in Chapter 2.

e

FFaaddeerr

A high-quality 100mm channel fader controls the level to all busses, and has 10dB

of gain when full up as well as an expanded scale around the critical unity gain area,

for maximum resolution.

Rr

MMUUTTEE

The Channel MUTE switch mutes all feeds from the input channel, and can be

remotely controlled by the consoles Mute Master section, allowing creation of up

to 8 mute groups. The integral LED illuminates when the Mute is active.

t

SSAAFFEE

A semi-recessed Mute SAFE switch allows the channel to be prevented from

remote muting by mute groups, but still allows it to be locally muted. Safe mode

is selected when the switch is pressed and internally illuminated.

y

PPFFLL

The PFL button is conveniently located below the fader, and provides a mono PFL

or stereo AFL feed to the engineers wedge output and headphones. Intercancel

or additive soloing is possible, with or without Input Priority, and solos can be

cleared with a single button press (SOLO CLEAR) at the master section.

The integral LED illuminates to indicate that a PFL is active.

u

LLEEDD iinnppuutt mmeetteerriinngg

The channel is fitted with a 10-segment peak-reading bargraph meter, positioned

next to each fader for maximum visibility and giving immediate and graphic

indication of incoming (pre-EQ) signals. The top (red) LED in the bar is configured

as a Peak LED, and monitors the signal path in three places, (pre-EQ, post-EQ and

post-fader) giving warning that the signal is within 3dB of clipping.

RNGE

4.4 SM20 Functional Description

iI

MMuuttee GGrroouupp AAssssiiggnnmmeenntt

Each input channel can be assigned to any combination of 8 mute groups, using the

recessed switch bank next to the fader. The corresponding mute master buttons

are located on the master module.

DDiirreecctt OOuuttppuutt

A balanced direct output is available on a male XLR on the rear panel. This is fed

from a pre-fade signal which can be jumper selectable to be pre or post-EQ, and

pre or post-mute, or may be jumper-selected as post-fade.

MMiicc SSpplliitt

A passive mic split output is available on a male XLR on the rear panel, for

feeding input signals to the FHO console in applications where a separate stage

splitter is not available. A pin 1 lift switch allows the pin 1 of this XLR to be

disconnected console chassis ground.

RReeaarrccoonn PPaanneell

The connections on the rearcon panel are as follows:

IINNPPUUTT XXLLRR && MMIICC SSPPLLIITT

Pin 1 Gnd (Screen)

Pin 2 Hot (In-phase signal)

Pin 3 Cold(Out-of-phase signal)

DDIIRREECCTT OOUUTT ((GGrroouunndd CCoommppeennssaatteedd)) ((BBaallaanncceedd ooppttiioonn))

Pin 1 Gnd (Screen) Gnd (Screen)

Pin 2 Signal Hot (In-phase signal)

Pin 3 Ground Sense Cold(Out-of-phase signal)

IINNSSEERRTT SSEENNDD ((GGrroouunndd CCoommppeennssaatteedd)) ((BBaallaanncceedd ooppttiioonn))

Tip Signal Hot (In-phase signal)

Ring Ground Sense Cold (Out-of-phase signal)

Sleeve Gnd (Screen) Gnd(screen)

IINNSSEERRTT RREETTUURRNN

Tip Hot (In-phase signal)

Ring Cold (Out-of-phase signal)

Sleeve Gnd(screen)

OOuuttppuutt MMoodduullee

RNGE

SM20 Functional Description 4.5

Each of the six Output Modules has two sections: The lower sections are

dedicated mono outputs, and the top sections are arranged as 6 pairs of controls

with a Global Mode switch which allows each pair to be configured as two monos

or one stereo output.

MMoonnoo OOuuttppuuttss 11--66

1

EEXXTT IINN

The EXT IN level control adjusts the level of an external input which can be

brought in via the balanced XLR for summing to the Output bus. The input is

enabled when the associated ON switch is pressed.

2

FFAADDEERR

The 100mm fader controls the final level to the electronically balanced output.

3

MMUUTTEE

The output is muted when the switch is pressed, and the integral LED illuminates

to show that the MUTE is active.

4

MMEETTEERR

A peak-reading 16-segment LED Bargraph Meter displays the level of the output

after the Talkback/Oscillator injection point. An optional VU meterbridge may

also be fitted.

5

AAFFLL

The AFL (After-Fade Listen) source is after the insert point. The AFL signal is

switched through to both AFL L and AFL R buses by the AFL switch. An integral

LED glows when AFL is active. The AFL may be switched off by pressing the AFL

switch again, or by the Solo Logic system which is controlled from the Master

Module.

6

AAFFLL TTRRIIMM

AFL TRIM adjusts the level of the AFL signal by +/-10dB.

7

GGRRPP TTOO LL//RR

The internally illuminated L and R switches route the post-mute, post-fade output

signal to the last pair of output busses (designated L and R) for subgrouping,

allowing the SM20 to be used as a Front-of-House mixer if necessary.

8

IINNSS ((OOUUTT))

The Insert Point consists of separate Send and Return jacks on the rear panel. The

Send is normalled to the Return.

The OUT switch bypasses the Insert Point when pressed, but leaves the pre-fade

output signal on the Send jack to feed external equipment if required. The switch

is illuminated when the insert is bypassed.

9

ØØ ((PPhhaassee))

Pressing the Ø (Phase) switch reverses the phase of the output, to allow

experimentation for best feedback immunity with a multiple-mic setup. The

switch is illuminated when the phase is reversed.

0

OOSSCC//TTBB

Pressing this latching switch arms the output to receive talkback, tone or pink

4.6 SM20 Functional Description

noise from the central talkback/oscillator section on the Master, when either the

master TALK TO OUTPUTS or OSC TO OUTPUTS switches are active. The

switch illuminates to warn the the OSC/TB is armed. The output is dimmed by

6dB when talkback is active. Alternatively, if the Master Talkback or Oscillator

signal is already active, pressing OSC/TB switch routes the Talkback or Oscillator

signal to the output, until the switch is released.

MMoonnoo//SStteerreeoo OOuuttppuuttss 77--1122

These outputs may either be configured as mono sends or as stereo pairs by

pressing the Global Mode (STE) switch (see

a

below).

q

EEXXTT IINN

The EXT IN level control adjusts the level of an external input which can be

brought in via the balanced XLR for summing to the Output bus. The input is

enabled when the associated ON switch is pressed.

w

FFAADDEERR

The 100mm fader controls the final level to the electronically balanced output.

e

MMUUTTEE

The output is muted when the switch is pressed, and the integral LED illuminates

to show that the MUTE is active.

r

MMEETTEERR

A peak-reading 16-segment LED Bargraph Meter displays the level of the output

after the Talkback/Oscillator injection point. An optional VU meterbridge may

also be fitted.

t

AAFFLL

The AFL (After-Fade Listen) source is after the insert point. The AFL signal is

switched through to both AFL L and AFL R buses by the AFL switch. An integral

LED glows when AFL is active. The AFL may be switched off by pressing the AFL

switch again, or by the Solo Logic system which is controlled from the Master

Module. In stereo mode the Solo switches are logic linked to give automatic stereo

AFL.

y

AAFFLL TTRRIIMM

AFL TRIM adjusts the level of the AFL signal by +/-10dB.

u

GGRRPP TTOO LL//RR

The L and R switches route the post-mute, post-fade output signal to the last pair

of output busses (designated L and R) for subgrouping, allowing the SM20 to be

used as a Front-of-House mixer if necessary.

i

IINNSS ((OOUUTT))

The Insert Point consists of separate Send and Return jacks on the rear panel. The

Send is normalled to the Return.

The OUT switch bypasses the Insert Point when pressed, but leaves the pre-fade

output signal on the Send jack to feed external equipment if required. The switch

is illuminated when the insert is bypassed.

o

ØØ ((PPhhaassee))

Pressing the Ø (Phase) switch reverses the phase of the output, to allow

experimentation for best feedback immunity with a multiple-mic setup. The

SM20 Functional Description 4.7

switch is illuminated when the phase is reversed.

p

OOSSCC//TTBB

Momentarily pressing this switch arms the output to receive talkback, tone or pink

noise from the central talkback/oscillator section on the Master, when either the

master TALK TO OUTPUTS or OSC TO OUTPUTS switches are pressed. The

switch illuminates to warn that OSC/TB is armed. The output is dimmed by 6dB

when talkback is active. Alternatively, if the Master Talkback or Oscillator signal is

already active, pressing and holding the switch for more than about one second

routes the Talkback or Oscillator signal momentarily to the output, until the

switch is released.

a

GGLLOOBBAALL MMOODDEE ((SSTTEE))

When STE is pressed the two upper outputs become a stereo pair. In this mode

the dual concentric sends on the input channels are automatically configured as a

stereo Level on top and Pan on the bottom, instead of two separate mono sends,

and the AFL buttons are linked. The integral LED illuminates to show when Stereo

mode is active.

RReeaarrccoonn PPaanneellss

The connections on the rearcon panes are as follows:

OOUUTTPPUUTT XXLLRR ,, EEXXTT II//PP ((oonn MMaasstteerr RReeaarrccoonn PPaanneell -- sseeee MMaasstteerr SSeeccttiioonn))

Pin 1 Gnd (Screen)

Pin 2 Hot (In-phase signal)

Pin 3 Cold(Out-of-phase signal)

IINNSSEERRTT SSEENNDD && RREETTUURRNN

Tip Hot (In-phase signal)

Ring Cold (Out-of-phase signal)

Sleeve Gnd(screen)

4.8 SM20 Functional Description

MMaasstteerr MMoodduullee

LL && RR OOuuttppuuttss

1

EEXXTT IINN

The EXT IN level control adjusts the level of an external input which can

be brought in via the balanced XLR for summing to the Output bus. The

input is enabled when the associated ON switch is pressed.

2

FFAADDEERR

The 100mm fader controls the level to the electronically balanced output.

3

MMUUTTEE

The output is muted when the switch is pressed, and the integral LED

illuminates to show that the MUTE is active.

4

MMEETTEERRSS

Peak-reading 16-segment LED Bargraph Meters display the level of the

Wedge output signal, which is normally PFL/AFL. However, when the L/R

TO WEDGE switch is ON, the Wedge output receives the L/R output

signal, and this will be displayed on these meters, although this selection is

always overridden by an active AFL/PFL. Note that if the optional VU

meterbridge is fitted, separate L/R.output meters are included.

5

AAFFLL

The AFL (After-Fade Listen) source is after the insert point. The AFL signal

is switched through to both AFL L and AFL R buses by the AFL switch. An

integral LED glows when AFL is active. The AFL may be switched off by

pressing the AFL switch again, or by the Solo Logic system which is

controlled from the Master Module. In stereo mode the Solo switches are

logic linked to give automatic stereo AFL.

6

AAFFLL TTRRIIMM

AFL TRIM adjusts the level of the AFL signal by +/-10dB.

7

IINNSS ((OOUUTT))

The Insert Point consists of separate Send and Return jacks on the rear

panel. The Send is normalled to the Return.

The OUT switch bypasses the Insert Point when pressed, but leaves the

pre-fade output signal on the Send jack to feed external equipment if

required. The switch is illuminated when the insert is bypassed.

8

ØØ ((PPhhaassee))

Pressing the Ø (Phase) switch reverses the phase of the output, to allow

experimentation for best feedback immunity with a multiple-mic setup.

The switch is illuminated when the phase is reversed.

9

OOSSCC//TTBB

Pressing this latching switch arms the output to receive talkback, tone or

pink noise from the central talkback/oscillator section on the Master, when

either the master TALK TO OUTPUTS or OSC TO OUTPUTS switches

are active. The switch illuminates to warn the the OSC/TB is armed. The

output is dimmed by 6dB when talkback is active. Alternatively, if the

Master Talkback or Oscillator signal is already active, pressing OSC/TB

switch routes the Talkback or Oscillator signal to the output, until the

switch is released.

SM20 Functional Description 4.9

0

GGLLOOBBAALL MMOODDEE ((SSTTEE))

When STE is pressed the two upper outputs become a stereo pair. In this mode

the dual concentric sends on the input channels are automatically configured as a

stereo level on top and pan on the bottom, instead of two separate mono sends.

The integral LED illuminates to show when Stereo mode is active.

WWeeddggee MMoonniittoorr SSeeccttiioonn

q

WWEEDDGGEE FFAADDEERR

A stereo 100mm fader is provided for engineers Wedge speakers, and this

normally receives any PFL or AFL signals when an input or output SOLO button is

pressed. When no solos are selected, the Wedge output is normally silent, unless

the L/R to Wedge switch is pressed (see

r

below), in which case the L/R

outputs are heard, or an external AFL/PFL is present.

w

MMOONNOO SSOOUURRCCEE LL && RR

Mono source buttons L and R allow either the Left or Right monitor/solo signals to

be fed to both left and right wedge outputs, or if both are pressed, a mono sum of

left and right monitor/solo signals is fed to both left and right wedge outputs. The

switches illuminate when active.

e

AALLTT WWEEDDGGEE

An Alternate Wedge stereo output is provided, with its own level control.

Pressing the internally illuminated ON switch enables the Alternate Wedge output

and mutes the main wedge, allowing monitoring on either one or another type of

speaker. (for example a standard wedge or an in-ear radio system).

The Alt Wedge is normally sourced post the main wedge fader, but may be

switched to pre-fade by pressing the associated PRE switch.

r

LL//RR TTOO WWEEDDGGEE

The Wedge speakers normally receive any PFL or AFL signals when an input or

output SOLO button is pressed. When no solos are selected, the Wedge output is

normally silent, unless the L/R TO WEDGE switch is pressed (in which case the

L/R outputs are heard) or an external AFL/PFL is present. The switch illuminates

when ON.

t

PPHHOONNEESS

The operators phones are fed by the same signal as the Wedge, but have a

separate phones volume control.

The headphone socket is recessed into the front of the master fascia, and is driven

by a high-power (350mW into 8ohms) headphone amp.

Return talkback from another Soundcraft console is automatically switched onto

the headphones, dimming the programme signal.

y

LLAAMMPP DDIIMMMMEERR

The Lamp Dimmer controls the voltage to the 4-pin XLR socket which is provided

for the connection of Littlites.

The pinout is as follows:

Pin 1 & 3 +/-12V

Pin 4 0v

max. current 400mA

u

PPSSUU RRAAIILLSS

Three LEDs monitor the status of the power supply rails.

4.10 SM20 Functional Description

TTaallkkbbaacckk aanndd OOsscciillllaattoorr SSeeccttiioonn

The talkback and oscillator sections have similar routing systems, allowing

them to access any of the console busses. The talkback section has front and

rear panel mic input XLRs, with phantom power capability. The mic signal can

be routed either to selected internal busses, or sent to a Soundcraft

proprietary intercom output (compatible with Series FIVE or another SM

monitor console).

i

TTAALLKKBBAACCKK MMIICC

Talkback Mic input XLRs are provided on the front and rear panel, with 48V

phantom power capability when the 48V switch is pressed.

o

LLEEVVEELL

This control adjusts the gain of the Talkback Mic preamp over a 30dB range.

p

FFOOHH TTOO BBUUSSSSEESS

The FOH TO BUSSES (ON) switch allows any return talkback from the FOH

console to be routed directly to the monitor outputs via the TB/Osc buttons,

for use when the monitor engineer has to leave the console unattended during

setup or soundcheck. The FOH talkback is enabled when the switch is

illuminated.

a

TTAALLKK TTOO FFOOHH

TALK TO FOH routes the talkback signal to the proprietary Soundcraft

intercom output (compatible with Series FIVE or another SM monitor console)

on the rear panel. When TALK TO FOH is active (LED illuminated) the FOH

TB OUT XLR on the rear panel carries the talkback signal plus a nominal 15V

DC superimposed on it to page the FOH console. The DC voltage may be

disabled by internal jumpers if required.

s

TTAALLKK TTOO OOUUTTPPUUTTSS ((TTBB//OOSSCC))

TALK TO OUTPUTS (TB/OSC) routes the talkback signal to any outputs

which have been previously armed for talkback (local TB switch ON). If the

switch is pressed momentarily, the switch latches. Alternatively, pressing and

holding the switch for more than about one second produces a momentary

action until the switch is released. The switch illuminates to warn that TB/OSC

is active.

OOSSCCIILLLLAATTOORR

The oscillator generates either tone or pink noise, and has its own

independent balanced XLR output on the rear panel. The oscillator can be

routed either individually to outputs, or to all busses simultaneously.

d

LLEEVVEELL

This control adjusts the oscillator level to both the XLR output and the internal

busses.

f

SSRRCC ((SSoouurrccee))

The oscillator generates either TONE (switch pressed and illuminated) from

63Hz to 10kHz, or pink noise (switch released).

g

xx1100

The normal frequency range of the oscillator is 63Hz to 1kHz. Pressing the

x10 switch (internal LED lit)provides a higher range of 630Hz to 10kHz.

SM20 Functional Description 4.11

h

OOSSCC TTOO XXLLRR OO//PP

The rear panel OSC OUT XLR is enabled when this switch is pressed. The

internal illumination indicates when the output is active.

j

OOSSCC TTOO AALLLL BBUUSSSSEESS

The Oscillator may be routed directly to all busses simultaneously by pressing the

OSC TO ALL BUSSES switch ON (switch illuminated) where it mixes with any

existing signal.

k

OOSSCC TTOO OOUUTTPPUUTTSS ((TTBB//OOSSCC))

OSC TO OUTPUTS (TB/OSC) routes the oscillator signal to any outputs which

have been previously armed for talkback or oscillator (local TB switch ON). If the

switch is pressed momentarily, the switch latches. Alternatively, pressing and

holding the switch for more than about one second produces a momentary action

until the switch is released. The switch illuminates to warn that TB/OSC is active..

l

PPFFLL TTRRIIMM

The PFL trim control gives +/-10dB of level adjustment to the input solo level

heard in the Wedge and Phones outputs. The output AFL solos have their own

individual trim controls on their respective output modules.

;

IINNPPUUTT PPRRIIOORRIITTYY

The INPUT PRIORITY (ON) switch, when selected, allows an input solo (PFL) to

temporarily override any output solo (AFL) which may be present. When the input

solo is released, the original output solo will reappear on the monitors. If

AUTOCANCEL (see below) is also ON, input PFLs still have priority, but PFLs

will only cancel other PFLs, and AFLs will only cancel other AFLs.

z

AAUUTTOO CCAANNCCEELL

The AUTOCANCEL (ON) button, when selected, allows any solo button selected

to cancel the previous solo. When this mode is not selected, solos can be selected

additively.

x

SSOOLLOO CCLLEEAARR

Pressing SOLO CLEAR cancels any solos on the console.

MMuuttee MMaasstteerrss

c

MMUUTTEE AALLLL OO//PPSS

The MUTE ALL O/Ps button allows total muting of all stage feeds. As protection

against accidental operation, this button has to be held down for 2 seconds before

it will activate. Inputs are not muted (Direct Outs will still be active), and soloing

to the wedge outputs can still take place. The outputs are restored when the

switch is released.

v

MMUUTTEE MMAASSTTEERRSS

8 recessed latching buttons control the mute status of any channels assigned to the

appropriate mute group.

Inputs may be assigned to any combination of the eight master mute busses.

When an input channel is assigned to a mute bus, it is muted when the

corresponding MUTE MASTER is pressed. The MUTE MASTER illuminates and

the input channel MUTE switch also illuminates to indicate that a non-local mute is

active.

4.12 SM20 Functional Description

CCoommmmss LLiinnkk

The Comms Link is designed to pick up the call signal from a Clear-Com

intercom and use this to flash the consoles Littlites in order to attract the

engineers attention. There is no connection to the Clear-Com audio,

which passes through unaffected.

The Comms Link will only operate if both the +30V Intercom supply and the

DC Call signal (+4Vdc to +11Vdc) are present on the Comms Link XLRs.

The Comms Link will also operate with the TW option on the Clear-Com

system where a second audio channel is superimposed on the +30Vdc.

OOppttiioonnaall VVUU MMeetteerrbbrriiddggee

An optional VU meterbridge can be installed and contains 22 VU meters for

metering of the 20 main outputs plus an additional pair of meters dedicated to

the Wedge output, which will meter any soloed signal on the console. All VU

meters are illuminated using LED backlighting, and each meter incorporates a

large peak LED which illuminates when the output is within 6dB of clipping.

BBSSSS VVaarriiccuurrvvee RReemmoottee CCoonnttrrooll

A unique feature on the SM20 allows the output solo buttons (in Autocancel

mode) on the console to automatically select the correct EQ page on the

FPC-900 Varicurve Remote Unit, using proprietary MIDI control. This saves

the engineer vital seconds as it avoids the need to solo the output and then

press the appropriate page button on the remote unit.

Note that this function requires the Varicurve remote to be fitted with

operating system EPROM V1.16 or above; contact BSS for further

information.

SM20 Functional Description 4.13

RReeaarrccoonn PPaanneell

The connections on the Master rear connector panel are as follows:

AAllll AAuuddiioo XXLLRRss

Pin 1 Gnd (Screen)

Pin 2 Hot (In-phase signal)

Pin 3 Cold(Out-of-phase signal)

CClleeaarr--CCoomm CCoonnnneeccttiioonn ((XXLLRR))

Pin 1 Common (DC ground & Intercom Low)

Pin 2 +30Vdc from Intercom System

Pin 3 Intercom Line (Audio & DC Call Signal)

AAFFLL//PPFFLL OOuutt

Tip Signal

Ring Ground Sense

Sleeve Gnd (Screen)

AAFFLL//PPFFLL BBuuss IInn

Tip Hot (In-phase signal)

Ring Cold (Out-of-phase signal)

Sleeve Gnd(screen)

4.14 SM20 Functional Description

SM20 Specifications 5.1

SSMM2200

SSppeecciiffiiccaattiioonnss

5

5.2 SM20 Specifications

SSMM2200 PPrroovviissiioonnaall SSppeecciiffiiccaattiioonnss

FFrreeqquueennccyy RReessppoonnssee

Any Input to any output 20Hz - 20kHz, +0/-0.5dB

TToottaall HHaarrmmoonniicc DDiissttoorrttiioonn

All measurements at 20dBu

Line In to Group or Mix Out Less than 0.005% @1kHz

Less than 0.025% @10kHz

NNooiissee

22Hz - 22kHz bandwidth, unweighted

Mic input Equivalent Input Noise Less than -127.5dBu (200Ω source)

Group Output Noise Less than -80dBu (40 ch routed)

Mix Output Noise Less than -80dBu (40 ch routed)

CCrroossssttaallkk

All measurements at 1kHz

Input Channel Muting Greater than 100dB

Input Channel Send Pot Isolation Greater than 75dB

Group Fader Isolation Greater than 95dB

Group to Group Crosstalk Less than -75dB

Group to Mix Crosstalk Less than -75dB

Mix to Group Crosstalk Less than -75dB

IInnppuutt aanndd OOuuttppuutt IImmppeeddaanncceess

Input 2kΩ balanced
All Insert Sends Less than 75Ω balanced
All Insert Returns Greater than 10kΩ balanced
Outputs Less than 75Ω balanced

IInnppuutt//OOuuttppuutt CCaappaabbiilliittyy

Maximum Input Level +30dBu

Input Insert Sends +20dBu into 2kΩ (Bal. +26dBu into 1kΩ)
Output Insert Sends +26dBu into 1kΩ

All Insert Returns +26dBu

All Balanced Outputs +26dBu into 1kΩ
Headphone Output +20dBu into 600Ω

+350mW into 8Ω

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Input Sensitivity (XLR) -2dBu to -70dBu, +10dBu to -20dBu

Input Insert Send/Return -2dBu nominal

Output Insert Send/Return +4dBu nominal

Outputs +4dBu for 0VU

PFL/AFL -2dBu nominal

Oscillator +4dBu nominal