User’s Guide
OctaMic XTC
The Professional’s Multiformat Solution
Professional Mic/Line/Instrument Preamp
8-Channel Microphone / Line AD-Converter
4-Channel Line/Phones DA-Converter
8-Channel Analog to AES / ADAT Interface
64-Channel MADI Interface
ADAT / AES / MADI Format Converter
24 Bit / 192 kHz Digital Audio
MIDI Remote Control
USB 2.0 Class Compliant Operation
24 Bit Interface
AutoSet
™
SteadyClock
™
QuickGain™
AES-3
AES-10
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User’s Guide OctaMic XTC © RME
Important Safety Instructions..................................4
General
1 Introduction ...............................................................6
2 Package Contents.....................................................6
3 Brief Description and Characteristics.....................6
4 First Usage – Quick Start
4.1 Controls - Connectors - Displays............................7
4.2 Quick Start ..............................................................9
5 Accessories...............................................................9
6 Warranty...................................................................10
7 Appendix..................................................................10
Usage and Operation
8 Front Panel Controls
8.1 Select Keys..........................................................14
8.2 Encoders..............................................................14
8.3 Menu Keys...........................................................15
8.4 Channel Menu......................................................16
8.5 Setup Menu..........................................................18
8.5.1 Options Menu..................................................18
8.5.2 Setups Menu...................................................20
8.6 Clock ....................................................................21
9 The Input Channel in Detail
9.1 Gain......................................................................22
9.2 Phantom Power....................................................22
9.3 AutoSet.................................................................23
9.4 Instrument / Line ..................................................23
10 Using Multiple Units with MADI
10.1 Delay Compensation............................................24
10.2 Compensation ID .................................................26
11 Remote Control
11.1 MIDI......................................................................26
11.2 MIDI over MADI....................................................26
Inputs and Outputs
12 Analog Inputs / Outputs
12.1 Mic / Line In (XLR) ...............................................28
12.2 Line In (TRS)........................................................28
12.3 Instrument In........................................................28
12.4 Phones / Line Out ................................................29
13 Digital Inputs and Outputs
13.1 AES / EBU............................................................30
13.2 ADAT Optical .......................................................31
13.3 MADI ....................................................................32
14 Word Clock
14.1 Word Clock Input and Output...............................34
14.2 Technical Description and Background...............35
14.3 Cables and Termination.......................................36
15 MIDI...........................................................................36
User’s Guide OctaMic XTC © RME
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Class Compliant Mode
16 General.....................................................................38
17 System Requirements............................................38
18 Operation.................................................................38
18.1 Useful Hints.......................................................39
18.2 Class Compliant under Windows/Mac OS X ....40
19 Supported Inputs and Outputs..............................41
20 Operation at the Unit ..............................................41
Technical Reference
21 Technical Specifications
21.1 Analog..................................................................44
21.2 Digital Inputs........................................................45
21.3 Digital Outputs .....................................................46
21.4 Digital...................................................................46
21.5 MIDI .....................................................................46
21.6 General................................................................47
21.7 Firmware..............................................................47
21.8 MADI User Bit Chart ............................................47
21.9 Connector Pinouts...............................................48
22 Technical Background
22.1 Terminology.........................................................50
22.2 Lock and SyncCheck...........................................51
22.3 Latency and Monitoring .......................................52
22.4 DS – Double Speed.............................................53
22.5 QS – Quad Speed ...............................................53
22.6 AES/EBU – SPDIF...............................................54
22.7 Signal to Noise ratio in DS- / QS-Operation........55
22.8 MADI Basics ........................................................56
22.9 SteadyClock.........................................................57
23 Block Diagram.........................................................58
24 MIDI Implementation OctaMic XTC
24.1 Basic SysEx Format ............................................56
24.2 Message Types - Commands..............................56
24.3 Table....................................................................57
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User’s Guide OctaMic XTC © RME
Important Safety Instructions
ATTENTION! Do not open chassis – risk of electric shock
The unit has non-isolated live parts inside. No user serviceable parts inside.
Refer service to qualified service personnel.
Mains
• The device must be earthed – never use it without proper grounding
• Do not use defective power cords
• Operation of the device is limited to the manual
• Use same type of fuse only
To reduce the risk of fire or electric shock do not expose this device to rain or
moisture. Prevent moisture and water from entering the device. Never leave
a pot with liquid on top of the device. Do not use this product near water, i. e.
swimming pool, bathtub or wet basement. Danger of condensation inside –
don't turn on before the device has reached room temperature.
Installation
Surface may become hot during operation – ensure sufficient ventilation.
Avoid direct sun light and do not place it near other sources of heat, like radiators or stoves. When mounting in a rack, leave some space between this
device and others for ventilation.
Unauthorized servicing/repair voids warranty. Only use accessories
specified by the manufacturer.
Read the manual completely. It includes all information necessary
to use and operate this device.
User’s Guide OctaMic XTC © RME
5
User’s Guide
OctaMic XTC
General
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User’s Guide OctaMic XTC © RME
1. Introduction
The OctaMic XTC is extremely versatile. It offers a hi-end 8-channel microphone preamplifier
with AD-conversion, compatible to hi-level line signals and Hi-Z instruments. A 4-channel DAconversion serves monitoring and as digital return path. The digital outputs ADAT, AES/EBU
and MADI exist also as inputs, providing insert capabilities as well as digital conversion and
splitting between these formats. In Class Compliant mode the XTC operates as audio interface
with current Macs, and when using a Camera Connection Kit even with the iPad. The latter is
especially interesting, as the XTC is equipped with any analog and digital I/Os, therefore being
the perfect universal interface for this platform. Add the sheer number of 24 I/O-channels in CC
mode, and the XTC is clearly on top of any comparable device.
2. Package Contents
Please check that your OctaMic XTC package contains each of the following:
• OctaMic XTC
• Power cord
• Manual
• 1 optical cable (TOSLINK), 2 m
3. Brief Description and Characteristics
The OctaMic XTC is a full range hi-end preamp and AD/DA-converter in reference quality, fully
remote controllable. In a standard 19" box with 1 unit height the device offers numerous extraordinary features like Intelligent Clock Control (ICC), SyncCheck, SteadyClock, QuickGain,
AutoSet, MIDI over MADI, and remote control via USB, MADI and MIDI.
• 8 balanced XLR microphone inputs
• 4 TRS line, 4 TS instrument inputs
• 85 dB gain range
• Analog input level from –53 dBu up to +32 dBu
• High-end circuitry with relay and super low-noise microphone front-end
• Large frequency range (200 kHz) with special EMI input filtering
• 2 unbalanced stereo line / phones outputs
• Near click-free gain changes
• AutoSet: Automatic gain reduction with multiple linking
• Current state can be stored to 6 user presets
• Fully remote controllable
• Word clock input and output
• SyncCheck tests and reports the synchronization status of the clock signals
• MIDI I/O
• 4 x AES/EBU Out per D-sub, 8 channels @ 192 kHz
• 2 x ADAT Out, 8 channels @ 96 kHz
• MADI I/O (64 channels @ 48 kHz)
User’s Guide OctaMic XTC © RME
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4. First Usage – Quick Start
4.1 Controls - Connectors - Displays
The front of the OctaMic XTC features eight Select keys, 32 status LEDs, two stereo TRS outputs, four menu keys, two rotary encoders with push functionality and a graphical colour display.
Each channel has three LEDs showing the current state
of PAD/INST, 48V and signal. The channel’s Select key
gives quick access to the gains of the corresponding
input channels, which are then immediately adjustable
via the rotary encoders 1 and 2. The display also
includes two level meters for exact level calibration.
When the Select key is held pressed two lines are shown
between 1 and 2, indicating stereo mode. Both channels
are then adjusted simultaneously by one encoder.
Input 1 to 4 include optional attenuation against too high input levels (PAD, -20 dB). This setting
is found in the CHANNEL menu. The 1/4"TRS input within the XLR socket operates like the
XLR input, but is 9 dB less sensitive.
The 1/4" TS inputs of channels 5 to 8 is unbalanced and has a high impedance. It is optimized
to be used with instruments, and also activated in the CHANNEL menu.
The key PHONES gives immediate access to the Phones output level by encoder 1, and a selection of the signal source by encoder 2. The volume of Phones 1/2 is directly controlled by
encoder 1 and 2 when the display shows the level meter overview.
The key GROUPS brings up the group screen. Encoder 1 changes between Group All and
Group 1 to 4. Encoder 2 changes all gains of the corresponding group simultaneously.
The key CHANNEL gives access to:
Pre Amp Gain Amount of amplification
AutoSet Gain Automatic gain reduction
Gain Group Select one of four groups
+48V Phantom power (XLR only)
PAD / Instrument Input attenuation -20 dB / Switch to 1/4" TS
Phase Invert Phase inversion (180°)
Mute Mutes the current channel
The key SETUP offers several options to configure the device. Encoder 1 changes between
Options and Setups. The sub-menus in Options, General Settings, Digital Routing, Clock and
MIDI Sources, are accessed with encoder 2.
Pressing any of these keys again exits the current menu and returns to the level meter overview.
In the STATE area 8 LEDs provide a quick overview. SYNC indicates whether the external signals word clock, AES, ADAT and MADI are present and valid. Incoming and outgoing MIDI data
is signaled in the MIDI area. CTRL I and CTRL O show in- and outgoing remote control commands, no matter which port is used. ALL I and ALL O signal general MIDI data, again on any
port. A more detailed display of the incoming data is included in the SETUP – Options – MIDI
Sources screen (see chapter 8.5).
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User’s Guide OctaMic XTC © RME
The rear panel of the OctaMic XTC has eight analog inputs, mains power, a USB 2.0 port, MIDI
I/O, word clock I/O, MADI I/O, ADAT I/O and AES/EBU I/O.
BALANCED MICROPHONE / LINE INPUTS (XLR/TRS combo socket): Eight balanced full
range mic/line/inst inputs with 85 dB gain range.
ADAT IN (TOSLINK): Optical ADAT input (clock synchronization, monitoring, format conversion).
ADAT OUT (TOSLINK): Two optical ADAT outputs. These carry full 8 channels in S/MUX2
mode (96 kHz), and 4 channels at 176.4 / 192 kHz.
WORD IN (BNC): In menu Options – Clock the input can be set to be terminated with 75 Ohms.
WORD OUT (BNC): Standard word clock output.
MADI I/O optical: Standard optical MADI ports.
AES/EBU I/O (25-pin D-sub): The D-sub connector provides four AES/EBU outputs (AD sig-
nals) and four AES/EBU inputs (clock synchronization, monitoring, format conversion). The 25
pin D-sub connector is wired according to the widely spread Tascam standard (pinout see
chapter 13.1). The AES I/Os are transformer-coupled. The high sensitivity type input accepts all
common digital sources, even SPDIF.
USB 2.0: Windows: Firmware update. Mac OS X: Class Compliant audio interface and firmware
update. iPad: Class Compliant audio interface via Camera Connection Kit.
MIDI I/O (5-pin DIN): MIDI input and output via 5-pin DIN jacks. Used to remote control the OctaMic XTC, and to transmit MIDI data via MADI or USB.
IEC receptacle for power connection. The specially developed, internal hi-performance switch
mode power supply lets the OctaMic XTC operate in the range of 100V to 240V AC. It is shortcircuit-proof, has an integrated line-filter, is fully regulated against voltage fluctuations, and suppresses mains interference.
User’s Guide OctaMic XTC © RME
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4.2 Quick Start
After connection of all cables and power-on of the device, the configuration of the OctaMic XTC
starts in the menu SETUP – Options - Clock. Choose a clock source and a sample rate.
The next step is the GAIN setting. Press the desired SELECT button and adjust the gain with
the encoders, so that the two level meters do not show overload.
The digital output to send out the converted analog signal is defined in SETUP – Options – Digi-
tal Routing. Press encoder 2 to navigate downwards through the list, for example to ADAT Out.
By turning encoder 2 the signal source of the ADAT output can be set to Mic 1-8 (default).
The OctaMic XTC stores all settings before switching off, and sets them automatically when
switching on the next time. The storing process is triggered 5 seconds after the last change.
5. Accessories
RME offers several optional components for the OctaMic XTC:
Part Number Description
OK0050 Optical cable, Toslink, 0.5 m (1.7 ft)
OK0100 Optical cable, Toslink, 1 m (3.3 ft)
OK0200 Optical cable, Toslink, 2 m (6.6 ft)
OK0300 Optical cable, Toslink, 3 m (9.9 ft)
OK0500 Optical cable, Toslink, 5 m 16.4 ft)
OK1000 Optical cable, Toslink, 10 m (32.8 ft)
BO25MXLR4M4F1PRO Digital Breakout Cable Pro, AES/EBU
25-pin D-sub to 4 x XLR male + 4 x XLR female, 1m (3.3 ft)
BO25MXLR4M4F3PRO same, 3 m (9.9 ft)
BO25MXLR4M4F6PRO same, 6 m (19.8 ft)
BO25M25M1PRO Digital D-sub cable Pro, AES/EBU
25-pin D-sub to 25-pin D-sub, 1m (3.3 ft)
BO25M25M3PRO same, 3m (9.9 ft)
BO25M25M6PRO same, 6m (19.8 ft)
BOB32 BOB-32, Universal breakout box, 19" 1 Unit height. The professional
digital AES/EBU breakout solution
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User’s Guide OctaMic XTC © RME
6. Warranty
Each individual OctaMic XTC undergoes comprehensive quality control and a complete test at
IMM before shipping. The usage of high grade components should guarantee a long and trouble-free operation of the unit.
If you suspect that your product is faulty, please contact your local retailer.
Audio AG grants a limited manufacturer warranty of 6 months from the day of invoice showing
the date of sale. The length of the warranty period is different per country. Please contact your
local distributor for extended warranty information and service. Note that each country may
have regional specific warranty implications.
In any case warranty does not cover damage caused by improper installation or maltreatment replacement or repair in such cases can only be carried out at the owner's expense.
No warranty service is provided when the product is not returned to the local distributor in the
region where the product had been originally shipped.
Audio AG does not accept claims for damages of any kind, especially consequential damage.
Liability is limited to the value of the OctaMic XTC. The general terms of business drawn up by
Audio AG apply at all times.
7. Appendix
RME news and further information can be found on our website:
http://www.rme-audio.com
Distributor: Audio AG, Am Pfanderling 60, D-85778 Haimhausen, Tel.: (49) 08133 / 918170
Manufacturer:
IMM Elektronik GmbH, Leipziger Strasse 32, D-09648 Mittweida
Trademarks
All trademarks and registered trademarks belong to their respective owners. RME, Hammerfall
and DIGICheck are registered trademarks of RME Intelligent Audio Solutions. QuickGain, SyncAlign, SyncCheck, SteadyClock and OctaMic XTC are trademarks of RME Intelligent Audio
Solutions. Alesis and ADAT are registered trademarks of Alesis Corp. ADAT optical is a trademark of Alesis Corp. S/MUX is copyright Sonorus. Microsoft and Windows are registered
trademarks of Microsoft Corp. Apple, iPad and Mac OS are registered trademarks of Apple Inc.
Copyright © Matthias Carstens, 07/2013. Version 1.0
All entries in this User's Guide have been thoroughly checked, however no guarantee for cor-
rectness can be given. RME cannot be held responsible for any misleading or incorrect information provided throughout this manual. Lending or copying any part or the complete manual or its
contents as well as the software belonging to it is only possible with the written permission from
RME. RME reserves the right to change specifications at any time without notice.
User’s Guide OctaMic XTC © RME
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CE / FCC Compliance
CE
This device has been tested and found to comply with the limits of the European Council Directive on the approximation of the laws of the member states relating to electromagnetic compatibility according to RL2004/108/EG, and European Low Voltage Directive RL2006/95/EG.
FCC
This equipment has been tested and found to comply with the limits for a Class B digital device,
pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses,
and can radiate radio frequency energy and, if not installed and used in accordance with the
instructions, may cause harmful interference to radio communications. However, there is no
guarantee that interference will not occur in a particular installation. If this equipment does
cause harmful interference to radio or television reception, which can be determined by turning
the equipment off and on, the user is encouraged to try to correct the interference by one or
more of the following measures:
- Reorient or relocate the receiving antenna.
- Increase the separation between the equipment and receiver.
- Connect the equipment into an outlet on a circuit different from that to which the receiver is
connected.
- Consult the dealer or an experienced radio/TV technician for help.
RoHS
This product has been soldered lead-free and fulfils the requirements of the RoHS directive.
ISO 9001
This product has been manufactured under ISO 9001 quality management. The manufacturer,
IMM Elektronik GmbH, is also certified for ISO 14001 (Environment) and ISO 13485 (medical
devices).
Note on Disposal
According to the guide line RL2002/96/EG (WEEE – Directive on Waste
Electrical and Electronic Equipment), valid for all european countries, this
product has to be recycled at the end of its lifetime.
In case a disposal of electronic waste is not possible, the recycling can
also be done by IMM Elektronik GmbH, the manufacturer of the OctaMic
XTC.
For this the device has to be sent free to the door to:
IMM Elektronik GmbH
Leipziger Straße 32
D-09648 Mittweida
Germany
Shipments not prepaid will be rejected and returned on the original sender's costs.
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User’s Guide OctaMic XTC © RME
User’s Guide OctaMic XTC © RME
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User’s Guide
OctaMic XTC
Usage and Operation
14
User’s Guide OctaMic XTC © RME
8. Front Panel Controls
8.1 Select Keys
The four channel keys labeled SELECT offer quick selection and setting of the gain. After
pressing one of the four keys the page Mic Gain of the corresponding pair is shown in the display. The gain can now be adjusted immediately with encoder 1 and 2. This method guarantees
an immediate access to the most important parameters of the device, and makes 8 separate
encoders (pots) on the front panel obsolete.
For a similar reason and despite the informative display the front panel still has dedicated LEDs
for signal and overload (bi-color SIG LED). If overload/distortion is caused by too high gain one
simply hits the key SELECT where the overload is displayed, to then reduce the gain with encoder 1 or 2 – lightning quick and intuitive.
Apart from the group function the typical pairs of channels (1/2, 3/4…) can be adjusted simultaneously directly from the front panel. Press and hold the SELECT key so that the display shows
two lines between the encoder symbols 1 and 2. This so called Linked or Ganging mode operates in a relative way, different gains of either channel are retained when changing them both.
8.2 Encoders
The encoders can be turned endlessly, but also pressed, adding a key function. Their current
functionality is clearly shown in the display. In general turning them either changes the current
parameter, or moves the selection/cursor horizontally to the next page. Pressing the encoders
moves the selection/cursor vertically, up with 1 and down with 2, as indicated by the arrows in
the display.
On the gain pages brought up by the channel’s SELECT key pressing encoder 1 and 2 activates the AutoSet function. The label AS in the display changes from light gray to solid black
(see picture in chapter 4.1).
Example: Press the key SETUP. The menu Setups is now
shown the display. The number 1 within the circle on the
right side indicates that by turning encoder 1 more pages
are available. In this case only one, Options. Setups itself
has no further sub-pages. By pressing encoder 2 the
cursor moves down, by pressing encoder 1 it moves back
up. On a selected field or entry, the 2 to the right indicates
that the current parameter can be changed by turning
encoder 2.
On the Options page several sub-pages exist, therefore a 2 is shown on the right side of those
sub-pages. By turning encoder 2 the pages Clock, MIDI Sources, General Settings and Digital
Routing are shown. The arrow under the 2 indicates that pressing encoder 2 the corresponding
page is entered, and settings can be changed then.
User’s Guide OctaMic XTC © RME
15
8.3 Menu Keys
The keys to the left of the display simplify navigation, as they directly jump to specific areas.
PHONES
This key brings up the Phones 1 screen, where the output
level can be directly controlled with encoder 1, and the
signal source with encoder 2. Pressing PHONES again
changes to Phones 2.
The volume of Phones 1/2 can be adjusted directly with
encoder 1 and 2 when the level meter overview is shown in
the display. In that case there is no choice for the signal
source.
GROUPS
The key GROUPS brings up the group screen. Encoder 1 changes between Group All and
Group 1 to 4. Encoder 2 changes all gains of the corresponding group simultaneously. Their
relative values (the differences of gains between channels) are retained.
Group All
Current group settings are ignored, all 8 channels are affected by gain changes.
Group 1 to 4
The channels not assigned to any group are shown in light
gray to the left (channel number) and right (current gain).
The level meter is always active for all channels. The
OctaMic XTC has 8 channels, therefore no more than 4
groups with 2 channels each can be defined. The group
assignment is defined in the menu CHANNEL - Gain
Group.
Pressing encoder 2 activates the currently selected group,
another push activates the AutoSet function (AS) for this
group. Pressing the encoder a third time switches both
functions off.
CHANNEL
This key gives access to the settings of the analog inputs
Mic 1 to 8, and the analog outputs Phones 1 and 2.
SETUP
Direct access to Setups and Options, the latter having the
sub-pages Clock, MIDI Sources, General Settings, MADI
Settings and Digital Routing. A screenshot is shown on the
left page (chapter 8.2).
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User’s Guide OctaMic XTC © RME
8.4 Channel Menu
Mic 1 to 8, Settings, has the following entries:
Pre Amp Gain
Sets the current gain/amplification. Choices are 0 dB, and +10 up to +65 dB in steps of 1 dB.
AutoSet Gain
Automatic overload protection by gain reduction in case of overload. AutoSet tries to keep a
headroom of 6 dB. Levels higher than -6 dBFS will permanently reduce the gain. To check set
the channels to a high gain and apply an input signal. The displayed gain will quickly decrease
to a gain that is appropriate. While AutoSet in the XTC is not exactly the same as in the RME
Micstasy (with extreme overloads distortion will occur for the fraction of a second before the
level is set correctly), it works quite well in real-world applications and will prevent distorted
recordings reliably.
AutoSet can be activated in CHANNEL as well as on the gain pages brought up by the channel’s SELECT key: a push on encoder 1 and 2 activates AutoSet. The label AS in the display
changes from light gray to black.
With grouped channels the field AutoSet Gain is grayed
out, activating AutoSet is then done in the Groups page.
To avoid shifts in panorama AutoSet should work ganged
with stereo channels, so that gain changes of one channel
are also applied to the other one. This function is part of the
groups and thus available for up to 8 channels
simultaneously. This also means that for using ganged
AutoSet a stereo pair (like Mic1/2) has to be defined and
activated explicit as group.
As soon as AutoSet reduces the gain the label AS, shown in the front display, changes its color
from black to blue.
Gain Group
Assigns channels to one of four groups. Choices are None or 1 to 4.
+48V
Activates phantom power for condenser microphones or special accessories (Alva Test Plug).
Phantom power should only be activated when condenser microphones that require such a
power supply are used, and only in the specific channel. Additionally always make sure the
microphone is plugged in first before the phantom power is switched on. The OctaMic XTC
turns on the phantom power smoothly (soft start). Connecting and disconnecting microphones
while phantom power is active causes a high voltage surge, which can destroy the sensitive
microphone input stage.
Phantom power is only applied to the XLR socket, the inner TRS contacts do not carry any voltage.
User’s Guide OctaMic XTC © RME
17
PAD (Channels 1-4)
Channels 1 to 4 have an optional attenuator directly at the input stage. PAD reduces the signal
level by -20 dB, avoiding overload when feeding high-level line signals. XLR and TRS socket
are active at the same time, no switching between them is required. An active PAD is signaled
by an LED on the front panel.
Instrument (Channels 5-8)
Channels 5 to 8 have a high impedance instrument input. This function switches from the XLR
to the TRS socket. The current state is signaled by an LED on the front panel.
Phase Invert
Phase changes the polarity (180°). Useful to fix wrongly soldered cables or to eliminate sound
and phase errors.
Mute
Muting a channel. Allows to remove a signal without the need to change the current gain.
Phones 1 and 2 has the following entries:
Volume
Sets the output level from -64 dB up to +6 dB, in steps of 1 dB. Mute is also available.
Balance
Adjustable from -1 (left) through 0 (middle) to +1 (right).
Source
Selection of the signal source. Play 1/2 and 3/4 relate to
software playback in Class Compliant mode. Mic 1 to 8
provides monophonic monitoring of the selected input, Mic
1/2 to 7/8 the same in stereo. Mic 1-8S performs a
mixdown of all 8 input channels to the Phones output.
Next choices are single channel and stereo channels of
the digital inputs ADAT, AES and MADI.
Mute
Mute of the phones output, without the need to change the current volume setting..
Phase Invert
Available settings are Off, Both, Left and Right.
Output Level
Can be set to Low or High.
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User’s Guide OctaMic XTC © RME
8.5 Setup Menu
SETUP offers several options to configure the device. Encoder 1 changes between Options and
Setups. The sub-menus in Options, General Settings, Digital Routing, Clock and MIDI Sources,
are accessed with encoder 2.
Pressing any of these keys again exits the current menu and returns to the level meter overview.
8.5.1 Options Menu
The page Clock has the following entries:
Clock Source
Choices are INT (Internal, Master), WCK (Wordclock), AES 1 to 4, MADI and ADAT.
Sample Rate
Choices are 32, 44.1, 48, 64, 88.2, 96, 128, 176.4 and 192
kHz. Setting the correct sample rate is even necessary in
slave mode, with external clocking via word or one of the
digital inputs. Only with AES the real current sample rate
can be detected. With the other S/MUX formats the user
has to inform the unit, whether the input signal is in the
single, double or quad speed range.
WCK Alw. Singl
Word Clock Always Single Speed. Choices are On or Off.
WCK Term.
Word clock termination for the word clock input – On or Off.
The page General Settings has the following entries:
MIDI Device ID
Adjustable from 0 to 7.
MIDI Contr. Thru
On or Off.
LCD Contrast
Adjustable from -20% to +20%. Default is 0%.
SW-Version
Shows the current version number and date of the internal
software.
User’s Guide OctaMic XTC © RME
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The page MADI Settings has the following entries:
Delay Comp.
Delay Compensation. Choices are Off, Manual, Auto-ID,
Auto-CA (Channel Assignment)
Compens. ID
Manual setting of the Compensation ID, from 1 to 8.
Grayed out when Auto-ID or Auto-CA are active.
MADI Format
Can be set to 56 or 64 channels.
MADI Frame
Can be set to 48k or 96k.
These options are explained in detail in chapter 10.
The page Digital Routing has the following entries:
ADAT Out
Sets the signal source of the ADAT output. Choices are Mic 1-8, ADAT In, AES In, MADI In in
groups of eight, Playback 1-8, 5-12, 9-16,13-20, 17-24.
ADAT 2 Out
See ADAT Out.
AES Out
See ADAT Out.
MADI 1-8 etc
See ADAT Out. All eight 8-channel groups of the MADI
output can be freely assigned to the above signal sources.
Recording
Inputs 1 to 8 are fixed to the USB (Class Compliant mode) recoding channels 1 to 8. The Class
Compliant mode of the XTC provides a total of 24 recording and playback channels each.
Channels 9 to 24 are freely assignable in this menu:
Rec. 9-16
Choices are Mic 1-8, ADAT In, AES In, MADI In in groups of 8 channels
Rec. 17-24
Choices are Mic 1-8, ADAT In, AES In, MADI In in groups of 8 channels
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User’s Guide OctaMic XTC © RME
The page MIDI Sources has the following entries:
In the lower part of the display 5 fields, one for each MIDI input, show incoming MIDI signals.
DIN ist he rear 5-pin socket, USB1/2 the according USB MIDI port (only available with an active
USB connection) and MADI, which – thanks to RME’s MIDI over MADI technology - can also
receive MIDI from other devices.
The field Contr. (Control) reacts only on dedicated remote control commands for the XTC.
Control (Inp.)
Defines from which port the XTC receives remote control commands. Choices are USB1,
USB2, MADI In, DIN In, Off.
USB MIDI 1 / USB MIDI 2
Defines the source of the data sent to the USB MIDI ports
1 or 2. Choices are USB1, USB2, MADI In, DIN In,
Control, Off. The source Control means feedback /
response / status data sent by the XTC.
MIDI DIN out
Defines the source of the data sent to the MIDI DIN
output. Choices are USB1, USB2, MADI In, DIN In,
Control, Off. The source Control means feedback /
response / status data sent by the XTC.
MIDI ov. MADI
Defines the source of the data sent via MIDI over MADI to the MADI output. Choices are USB1,
USB2, MADI In, DIN In, Control, Off. The source Control means feedback / response / status
data sent by the XTC.
8.5.2 Setups Menu
The page Setups, Load/Store all Settings, has the following entries:
Setup Select
Choices are memory slots 1 to 6 and Factory (factory
default).
Operation
Choices are Load and Store.
Start
Press 1s. Pressing and holding encoder 2 for at least one
second triggers the action selected in Operation.
User’s Guide OctaMic XTC © RME
21
8.6 Clock Section
Source and frequency of the unit’s clock are configured in Options – Clock. Clock Source offers
several choices for the current clock source: internal clock or external clock (WCK = Word
clock, AES 1 to 4, MADI, ADAT). Sample Rate sets the sample rate for both external and internal clock.
WCK, AES 1-4, MADI, ADAT (Slave Mode)
Activates the corresponding input as clock reference. In case of a missing or invalid clock
source signal the display of the current sample rate in the lower right corner of the display turns
to red, then the unit changes to its internal clock.
INT (Master Mode)
Activates the internal clock.
With a setting of INT (internal clock) it is mandatory that the clock rate of the sources is
synchronous to the OctaMic XTC. Therefore the external device has to be synchronized to
the OctaMic XTC word clock output or AES/ADAT/MADI output.
The OctaMic XTC thus has to be master, all devices connected to it must be slave. In order to
avoid clicks and drop outs due to faulty or missing synchronicity, a special process called
SyncCheck compares the incoming data and the OctaMic XTC internal clock. The sync state is
indicated by a flashing (error) or constantly lit (OK) STATE LED.
A selection of Double and Quad Speed is also possible when using external clock (Slave). If the
OctaMic XTC should operate at 192 kHz, but receives a synchronous word clock of 48 kHz, set
Sample Rate to that value. This way, AD/DA-conversion and digital outputs are configured to
operate in the frequency ranges Single Speed, Double Speed or Quad Speed.
Single Speed
All outputs carry a signal in the range of 32 kHz up to 48 kHz.
DS (Double Speed)
The AES outputs 1-8 carry a signal in the range of 64 kHz up to 96 kHz. ADAT and MADI stay
at no higher than 48 kHz, with the data transmitted in the S/MUX format.
QS (Quad Speed)
The AES outputs 1-8 carry a signal in the range of 176.4 kHz up to 192 kHz. ADAT and MADI
stay at no higher than 48 kHz, with the data transmitted in the S/MUX4 format. Therefore ADAT
is limited to 4 channels (2 per optical output) in this mode.
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User’s Guide OctaMic XTC © RME
9. The Input Channel in Detail
9.1 Gain
The OctaMic XTC GAIN can be set in steps of 1 dB per channel. Setting the amount of amplification is done digitally, therefore being very accurate and 100% reproducable. The gain change
itself is performed within the analog domain.
The range of the adjustable gain is
65 dB. Additionally an attenuator
(PAD) of -20 dB is available. The
total gain range is therefore 85 dB.
The TRS Line input gain range is
shifted by about 9 dB. The ADconverter in the OctaMic XTC
reaches full scale already at an
input level of –53 dBu (Gain 65 dB,
XLR input), but also at +32 dBu
(Gain 0 dB, PAD active). Therefore
the inputs are both sophisticated
microphone and line types.
The picture to the right shows
levels and gains in an overview and
in relation to the different inputs.
The instrument input has no PAD,
and a gain range of 55 dB.
XLR and TRS Line have a gain
range of 55 dB in steps of 1 dB,
and another step of 10 dB.
Additionally a PAD of -20 dB with
XLR and -18 dB with TRS Line is
available.
9.2 Phantom Power
The LED +48V indicates activated phantom power for the XLR input. Phantom power should
only be activated when using condenser microphones which require such a power supply.
Connecting and disconnecting microphones while phantom power is active causes a high
voltage surge, which can destroy the microphone input stage! Switch phantom power off
before connecting/disconnecting any external device.
The OctaMic XTC turns on the phantom power smoothly during one second, from 0 to 48 Volts.
This technique is advantageous for the connected microphone as well as the OctaMic XTC.
The phantom power of the OctaMic XTC is short-circuit proof. With a maximum load on all eight
channels the internal voltage from the power supply does not drop below 47 Volts.
User’s Guide OctaMic XTC © RME
23
9.3 AutoSet
Some preamps include limiters in order to prevent clipping, especially of the A/D converter
stage. Such a circuitry is not feasible for the OctaMic XTC, because it would spoil the mic preamp's excellent technical data.
But as the OctaMic XTC's gain is controlled completely digitally, the device can set it automatically, thus providing perfect protection from overload with no degradation of the audio signal,
which does not have to pass any additional electronic circuits.
Since AutoSet operates as overload protection and not as 'compressor', there is no automatic
gain increase. AutoSet only reduces gain. And with AutoSet activated, the gain can still be
changed manually. The currently highest possible value can not be exceeded, because AutoSet
will reduce the gain in real-time during the manual change.
In practice, there are two possible ways to work with AutoSet:
• Gain of all channels is set to a rather high value, e.g. 60 dB. Then a rehearsal with maximum
acoustic level is performed. Thereafter AutoSet is switched off.
• As above, with AutoSet permanently active.
There are good reasons for both of these alternatives. Thanks to the flexible threshold setting
and easy manual correction of set values, the OctaMic XTC is fit for all applications.
AutoSet can be activated in CHANNEL as well as on the gain pages brought up by the channel’s SELECT key: a push on encoder 1 and 2 activates AutoSet. The label AS in the display
changes from light gray to black.
With grouped channels the field AutoSet Gain is grayed out, activating AutoSet is then done in
the Groups page.
To avoid shifts in panorama AutoSet should work ganged with stereo channels, so that gain
changes of one channel are also applied to the other one. This function is part of the groups
and thus available for up to 8 channels simultaneously. This also means that for using ganged
AutoSet a stereo pair (like Mic1/2) has to be defined and activated as group.
As soon as AutoSet reduces the gain the label AS, shown in the front display, changes its color
from black to blue.
9.4 Instrument
The 1/4" TS instrument input of channels 5 to 8 allow to attach both line signals as well as instrument signals. It handles standard line sources like keyboards, mixing desks, effects devices
or consumer-type units perfectly well. With its input impedance of 800 kOhm it also serves
perfectly as instrument input. The maximum input level is +21 dBu unbalanced. PAD is not
available.
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User’s Guide OctaMic XTC © RME
10. Using Multiple Units with MADI
Devices like the OctaMic XTC can be connected serially via MADI, and then transmit up to 64
channels (with up to 8 XTC) over one single MADI cable. In the menu Digital Routing the user
can decide at which place of the 64-channel MADI stream the current eight channels of the XTC
are inserted.
When multiple devices are connected serially, the MADI I/O of each OctaMic XTC causes a
delay of several samples. This problem is solved by the function Delay Compensation. Its settings are found in SETUP – Options - MADI Settings.
10.1 Delay Compensation
Default: 0ff. Available settings: Off, Manual, Auto-ID, Auto-CA
When multiple devices are connected serially, the MADI I/O of each OctaMic XTC causes a
delay of 3 samples. Therefore at the MADI output of the last device, the data of all upstreamed
devices are delayed. At Double Speed the delay rises to 6 samples per unit, at Quad Speed to
12 samples.
Delay Compensation delays the signals in a way that they are sample-synchronous in multidevice operation.
Delay Compensation has to be manually activated in each unit!
The following table lists the delay in samples from two up to eight units connected serially.
When using four units, the data of the first unit are delayed by 9 samples to the last unit, the
units 2 and 3 are delayed by 6 and 3 samples respectively. At Double Speed and Quad Speed
the values rise. Please note that in Double Speed no more than four, in Quad Speed no more
than two OctaMic XTC can be used serially with MADI.
Units Delay Delay DS Delay QS DC DC DS DC QS
2 3 6 12 21 18 12
3 6 12 - 21 18 4 9 18 - 21 18 5 12 - - 21 - 6 15 - - 21 - 7 18 - - 21 - 8 21 - - 21 - -
Inputs and outputs are delayed in different ways. With the inputs the delay equals the values
shown in the table. When using multiple units in serial cabling, the input data of the second unit
is delayed by 3 samples, the input data of the third by 6 samples and so on. This way, at the
end of the chain all input data are sample-aligned again. Chapter 13.3 shows a diagram to illustrate the setup.
The XTC’s Delay Compensation affects not only the analog inputs, but the digital ones as well.
For example additional AD-converters connected to the ADAT inputs and inserted into the
MADI stream – all the converters analog inputs fed to multiple XTCs will be sample-aligned
again.
Even the analog outputs of the XTC use the Delay Compensation. For technical reasons here
the delay is a fixed constant of 21 samples in Single Speed, no matter how many devices are
connected serially. In Double Speed the delay is 18, in Quad Speed 12 samples. The in most
cases slightly increased delay is outweighed by the big advantage of sample-aligned analog
outputs across multiple units.
21 samples @ 48 kHz
equal 437 µs.
18 samples @ 96 kHz
equal 187 µs.
12 samples @ 192
kHz equal 62.5 µs.
User’s Guide OctaMic XTC © RME
25
Manual
With this setting active, the user has to enter the Compens. ID (Compensation ID) manually.
The value must equal the position of the device within the chain.
Auto-ID
OctaMic XTC detects other devices sitting in front of it within the chain. If none is detected the
ID is set to 1, else according to the found ID plus 1. The entry Compens. ID is grayed out, because no longer manually adjustable.
Auto-CA
The option Auto Channel Assignment sets the digital routing according to the current ID. For
example the third OctaMic XTC in a chain will automatically use channels 17-24 in the MADI
data stream.
This is the most comfortable, fastest and safest way to use several devices serially. Simply set
Delay Comp. in all units to Auto-CA, quickly check the IDs in the display, and you’re ready to
enjoy all channels within just one MADI cable and sample-aligned.
10.2 Compensation ID
Default: 1. Available settings: 1, 2, 3, 4, 5, 6, 7, 8
In Auto-CA mode, the ID defines the 8-channel group within the MADI signal that is used to
insert the device's audio data:
ID 1: channels 1-8 ID 2: channels 9-16 ID 3: channels 17-24
ID 4: channels 25-32 ID 5: channels 33-40 ID 6: channels 41-48
ID 7: channels 49-56 ID 8: channels 57-64
When several OctaMic XTC, ADI8-QS or ADI-642 units are connected via MADI, Auto-ID helps
to set up all units correctly. In special cases, it may be desirable to set the ID manually, e.g. if
the first device in a MADI chain does not support the Auto-ID mode, or if a group of eight channels needs to be routed or processed in a particular way.
26
User’s Guide OctaMic XTC © RME
11. Remote Control
11.1 MIDI
The OctaMic XTC can be completely remote controlled via MIDI. It reacts on special SysEx
commands. Furthermore, upon request it will report the complete device status. Each OctaMic
XTC can be programmed with its own ID (menu Options - General Settings), providing a separated remote control of multiple devices via a single MIDI channel. A description of the MIDI
implementation is found in chapter 19.
The menu Options – MIDI Sources is used to define from which port the XTC receives MIDI
remote control commands: USB1, USB2, MADI In or DIN In. The option OFF is a safety setting
to prevent unexpected changes by MIDI signals.
In the same menu the output for the unit’s response to external remote commands is chosen.
All MIDI ports of the XTC, USB 1/2, DIN and MADI, are available as Control output, even at the
same time.
In the menu General Settings it is even possible to activate a through-mode of the complete
MIDI signal from the Control input to the Control output port. This option is especially useful with
serial MADI cabling, as remote commands would otherwise get stuck already at the first unit
within the MADI chain.
11.2 MIDI over MADI
MADI allows for a transmission of 64 audio channels over long distances with a single line –
perfect. But what about MIDI? Be it remote control commands or sequencer data, in practice
only a single MADI line will not suffice. Therefore RME developed the MIDI over MADI techno-
logy. The data at the MIDI input are being included into the MADI signal invisibly, and can be
collected at the MIDI output of another OctaMic XTC or other RME MADI device at the other
end of the MADI line.
Technically every single MADI channel includes several additional bits, containing various information (Channel Status). RME use the usually unused User bit of channel 56 (channel 28 in
96k frame mode), to transmit MIDI data invisibly within MADI, ensuring full compatibility.
To remote control more than one OctaMic XTC every unit can have its own ID (menu Options -
General Settings), providing a separated remote control of multiple devices via a single MIDI
channel.
User’s Guide OctaMic XTC © RME
27
User’s Guide
OctaMic XTC
Inputs and Outputs
28
User’s Guide OctaMic XTC © RME
12. Analog Inputs / Outputs
12.1 Mic / Line In (XLR)
The OctaMic XTC has 8 balanced full range XLR inputs on the back panel. The electronic input
stage is built in a servo balanced design which handles unbalanced and balanced signals correctly, automatically adjusting the level reference.
When using unbalanced cables be sure to connect pin 3 (-) to 1 (ground). Otherwise noise
may occur, caused by the unconnected negative input of the balanced input.
The pin assignment follows international standards. With XLR, pin 2 is + or hot, pin 3 is – or
cold, pin 1 is ground. Pin 1 is connected to the chassis directly at the socket (AES48).
The OctaMic XTC offers an adjustable amplification from -20 dB up to +65 dB. This equals a
sensitivity of +32 dBu down to –53 dBu, referenced to full scale of the AD-converter. Changing
the gain is usually done click-free, as the gain change is performed during the zero crossing of
the audio signal, if possible.
The soft switching, hi-current phantom power (48 Volt) provides a professional handling of condenser microphones. The usage of a hi-end integrated circuit (PGA 2500) plus a fully symmetrical signal path guarantees outstanding sound quality, stunning low THD, and maximum Signal
to Noise ratio in any gain setting.
Due to the XTC’s flexibility, its signal to noise ratio is not easy to determine. The EIN value is
constant across a very wide amplification range, typically 127 dBu at 150 Ohm input impedance. Even at a gain setting of 30, which corresponds to 0 dBFS at only -18 dBu, the EIN still
reaches 122 dBu.
12.2 Line In (TRS)
TRS sockets of inputs 1-4 operate as line inputs. Compared to the XLR inputs they have slightly
higher input impedance (6.6 kOhm) and a fixed attenuation of 9 dB. This jas no influence on
noise or distortion. Even the adjustable gain range is still 65 dB. But the PAD attenuates only by
18 dB, so that the input sensitivity covers +39 dBu down to -44 dBu, referenced to full scale of
the AD-converter.
12.3 Instrument In
The main difference between a line and an instrument input is its input impedance. Channels 58 offer an input impedance of 800 kOhm at the TS socket, with adjustable gain from +10 dB up
to +65 dB. This equals a sensitivity of +21 dBu down to -34 dBu, referenced to full scale of the
AD-converter.
User’s Guide OctaMic XTC © RME
29
12.4 Phones / Line Out
The OctaMic XTC has two unbalanced stereo 1/4" TRS outputs on the front. They are also special low impedance types, ready to be used with headphones. These channels are driven from a
high-quality DA-converter with 118 dBA Signal to Noise ratio. Additionally two hardware-based
reference levels are available. In the menu CHANNEL – Phones 1/2 the output level can be
chosen between High and Low. High equals an output level of +17 dBu at 0 dBFS, Low a level
of +4 dBV (+4.2 dBu). They can thus also be used as high-quality (yet unbalanced) line outputs.
Setting the output level, i.e. the monitoring volume, is done directly by turning the encoder knob
1 (Phones cannel 1/2) and 2 (Phones channel 3/4). Changing the monitoring volume is therefore very easy and quickly done.
In case the outputs should operate as
Line outputs, an adapter TRS plug to
RCA phono plugs, or TRS plug to TS
plugs is required.
The pin assignment follows international
standards. The left channel is
connected to the tip, the right channel to
the ring of the TRS jack/plug.
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User’s Guide OctaMic XTC © RME
13. Digital Inputs and Outputs
13.1 AES/EBU
The four AES/EBU inputs and outputs are provided on the rear of the OctaMic XTC via a 25 pin
D-sub connector with Tascam pinout. A digital breakout cable will provide 4 male and 4 female
XLR connectors. Every input and output is transformer-balanced, ground-free and compatible to
all devices with AES/EBU ports.
In normal operation the AES outputs carry the converted analog input signal. Via the menu Digi-
tal Routing also ADAT, USB, MADI and even AES can be chosen as source.
Besides the audio data, digital signals in SPDIF or AES/EBU format contain a channel status
coding, which is being used for transmitting further information. The output signal coding of the
OctaMic XTC has been implemented according to AES3-1992 Amendment 4:
• 32 kHz, 44.1 kHz, 48 kHz, 64 kHz, 88.2 kHz, 96 kHz, 176.4 kHz, 192 kHz according to the
current sample rate
• Audio use
• No Copyright, Copy permitted
• Format Professional
• Category General, Generation not indicated
• 2-Channel, No Emphasis
• Aux bits audio use, 24 bit
• Origin: HDSP
Connecting devices with coaxial SPDIF
ports to the OctaMic XTC outputs is accomplished by simple cable adapters
XLR/RCA. To achieve this, pins 2 and 3 of
an XLR plug are being connected to the two
contacts of a Phono/RCA plug. The ground
shield of the cable is only connected to pin
1 of the XLR plug.
Note that most consumer HiFi equipment with phono (SPDIF) inputs will only accept signals
with Channel Status ‘Consumer’! In such cases the above adapter cable will not work.
The OctaMic XTC supports Single Wire only, in the range of 32 kHz up to 192 kHz: a total of 8
channels, 2 channels per AES wire. The effective sample frequency equals the clock on the
AES wire. In case a conversion from/to Single, Double and Quad Wire is required, the RME
ADI-192 DD, an 8-channel universal sample rate and format converter, is highly recommended.
Pinout of the D-sub connector, Outputs
Signal Out
1/2+
Out
1/2-
Out
3/4+
Out
3/4-
Out
5/6+
Out
5/6-
Out
7/8+
Out
7/8-
D-Sub 18 6 4 17 15 3 1 14
GND is connected to pins 2, 5, 8, 11, 16, 19, 22, 25. Pin 13 is not connected.
User’s Guide OctaMic XTC © RME
31
The input AES 1 to 4 (channel 1-8) found on the D-sub connector can be used for audio (Digital
Routing) but also as clock source. Thanks to a highly sensitive input stage, a SPDIF signal can
also be fed by using a simple cable adapter phono/XLR (see above).
Pinout of the D-sub connector, Inputs
Signal In
1/2+
In
1/2-
In
3/4+
In
3/4-
In
5/6+
In
5/6-
In
7/8+
In
7/8-
D-sub 24 12 10 23 21 9 7 20
13.2 ADAT Optical
The OctaMic XTC provides two digital outputs in ADAT optical format. In normal operation
these ports carry the converted analog input signal. Via the menu Digital Routing also AES,
USB, MADI and even ADAT can be chosen as source.
In Single Speed mode both outputs can carry the same audio data, when set up accordingly in
Digital Routing. With this it is possible to distribute the output signal to two different devices.
When operating with sample rates higher than 48 kHz the entry ADAT 2 in the menu Digital
Routing will be grayed out. The OctaMic XTC then is in S/MUX mode, and will send the source
signal selected for ADAT 1 also at the ADAT 2 port.
As the ADAT optical signal is physically specified up to 48 kHz only, the OctaMic XTC automatically activates Sample Split mode (S/MUX) at 88.2 and 96 kHz, distributing the data of one
channel to two output channels. The internal frequency stays at 44.1/48 kHz. Therefore the
sample clock at the ADAT outputs is only half the frequency of the AES outputs. As interesting
as this is – you don't need to think about it. 96 and 192 kHz capable ADAT hardware, like all
current RME digital interfaces, re-combine the data automatically. The user (and the DAW software) does not see any split data, but just single channels at the expected double sample rate.
The ADAT outputs can be used at up to 192 kHz, but in QS mode only channels 1 to 4 will be
available.
The ADAT optical outputs of the OctaMic XTC are fully compatible to all ADAT optical inputs. A
usual TOSLINK cable is sufficient for connection.
ADAT Main
Interface for the first or only device receiving an ADAT signal from the OctaMic XTC. Carries
the channels 1 to 8. When sending a Double Speed signal, this port carries the channels 1 to 4.
In Quad Speed mode this port carries channels 1 and 2.
ADAT AUX
In Single Speed mode carries the source signal set for ADAT 2 in Digital Routing. When sending a Double Speed signal, this port carries the channels 5 to 8 of the source signal set for
ADAT 1. In Quad Speed mode this port carries the channels 3 and 4 of the source signal set for
ADAT 1.
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User’s Guide OctaMic XTC © RME
13.3 MADI
The optical MADI I/O provides the OctaMic XTC with a 64-channel MADI input and output. The
menu Digital Routing determines on which channels the XTC transmits its data (see chapter
8.5.1).
The MADI input will operate as an optional clock source (menu Clock) as well as a through input. Since each OctaMic XTC uses only 8 channels, up to 56 channels can be passed through,
switching this function off even all 64.
This technique is used to serially cascade several OctaMic XTC. Incoming MADI data is passed
through unchanged, only one block of eight channels is replaced. This allows up to 8 devices to
be connected serially. All 64 combined channels are available at the last device's output. The
the block of eight channels used by an individual device is determined either automatically
(Auto-CA) or manually (Compens. ID) in the menu MADI Settings:
ID 1: channels 1-8 ID 2: channels 9-16 ID 3: channels 17-24
ID 4: channels 25-32 ID 5: channels 33-40 ID 6: channels 41-48
ID 7: channels 49-56 ID 8: channels 57-64
The configuration of the MADI output signal is also done in the MADI Settings menu. MADI
Format sets the format to 56 or 64 channels. MADI Frame sets the format to 48k Frame or 96k
Frame when operating at 88.2 and 96 kHz. Sample rates higher than 48 kHz can be transmitted
with the standard 48k Frame as well, but then there is no automatic detection of the real sample
rate. This is the main advantage of the 96k Frame, but not all MADI devices support that format.
The OctaMic XTC can also be remote controlled via MADI. At the same time MIDI data are
transmitted via MADI, see chapter 11.2.
When multiple devices are connected serially, the MADI I/O of each OctaMic XTC causes a
delay of 3 samples. Therefore at the MADI output of the last device, the data of all upstreamed
devices are delayed. At Double Speed the delay rises to 6 samples per unit, at Quad Speed to
12 samples.
The problem of this offset is solved by the function Delay Compensation, see chapter 10.1. It
delays the signals in a way that they are sample-synchronous in multi-device operation. The
diagram on the next page shows a serial setup with HDSPe MADI card, three OctaMic XTC and
activated Delay Compensation with automatic channel assignment (Auto-CA).
Delay Compensation has to be manually activated in each unit!
User’s Guide OctaMic XTC © RME
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User’s Guide OctaMic XTC © RME
14. Word Clock
14.1 Word Clock Input and Output
SteadyClock guarantees an excellent performance in all clock modes. Its highly efficient jitter
suppression refreshes and cleans up any clock signal, and provides it as reference clock at the
BNC output (see section 18.10).
Input
The OctaMic XTC word clock input is active when WCK is chosen in the clock section. The
signal at the BNC input can be Single, Double or Quad Speed, the OctaMic XTC automatically
adapts to it. As soon as a valid signal is detected, the WCK LED is constantly lit, otherwise it is
flashing.
Thanks to RME's Signal Adaptation Circuit, the word clock input still works correctly even with
heavily mis-shaped, dc-prone, too small or overshoot-prone signals. Thanks to automatic signal
centering, 300 mV (0.3V) input level is sufficient in principle. An additional hysteresis reduces
sensitivity to 1.0 V, so that over- and undershoots and high frequency disturbances don't cause
a wrong trigger.
The word clock input is shipped as high impedance type (not terminated). The menu Clock -
WCK Term. has an option to activate internal termination with 75 Ohms.
Output
The OctaMic XTC's word clock output is constantly active, providing the current sample frequency as word clock signal. In master mode, the word clock will be fixed to 44.1 kHz or 48 kHz
(DS x 2, QS x 4). In any other case the sample rate is identical to the one present at the currently chosen clock input. When the current word clock source fails, the last valid sample rate
will be held automatically.
Selecting the option WCK Alw. Singl in the menu Clock causes the word clock output to always
stay within the range of 32 kHz to 48 kHz. So at 96 kHz and 192 kHz sample rate, the output
word clock is 48 kHz.
The word clock signal received by the OctaMic XTC can be distributed to other devices by using
the word clock output. With this the usual T-adapter can be avoided, and the OctaMic XTC operates as Signal Refresher. This kind of operation is highly recommended, because
• Input and output are phase-locked and in phase (0°) to each other
• SteadyClock removes nearly all jitter from the input signal
• the exceptional input (1 Vpp sensitivity instead of the usual 2.5 Vpp, dc cut, Signal Adapta-
tion Circuit) plus SteadyClock guarantee a secure function also with most critical word
clock signals.
Thanks to a low impedance, but short circuit proof output, the OctaMic XTC delivers 4 Vpp to 75
Ohms. For wrong termination with 2 x 75 Ohms (37.5 Ohms), there are still 3.3 Vpp at the output.
User’s Guide OctaMic XTC © RME
35
14.2 Operation and Technical Background
In the analog domain one can connect any device to another device, synchronization is not
necessary. Digital audio is different. It uses a clock, the sample frequency. The signal can only
be processed and transmitted when all participating devices share the same clock. If not, the
signal will suffer from wrong samples, distortion, crackle sounds and drop outs.
AES/EBU, SPDIF, ADAT and MADI are self-clocking, an additional word clock connection in
principle isn't necessary. But when using more than one device simultaneously problems are
likely to happen. For example any self-clocking will not work in a loop cabling, when there is no
'master' (main clock) inside the loop. Additionally the clock of all participating devices has to be
synchronous. This is often impossible with devices limited to playback, for example CD players,
as these have no SPDIF input, thus can't use the self clocking technique as clock reference.
In a digital studio synchronisation is maintained by connecting all devices to a central sync
source. For example the mixing desk works as master and sends a reference signal, the word
clock, to all other devices. Of course this will only work as long as all other devices are
equipped with a word clock or sync input, thus being able to work as slave (some professional
CD players indeed have a word clock input). Then all devices get the same clock and will work
in every possible combination with each other.
Remember that a digital system can only have one master! If the OctaMic XTC uses its
internal clock, all other devices must be set to ‘Slave’ mode.
But word clock is not only the 'great problem solver', it also has some disadvantages. The word
clock is based on a fraction of the really needed clock. For example SPDIF: 44.1 kHz word
clock (a simple square wave signal) has to be multiplied by 256 inside the device using a special PLL (to about 11.2 MHz). This signal then replaces the one from the quartz crystal. Big
disadvantage: because of the high multiplication factor the reconstructed clock will have great
deviations called jitter. The jitter of a word clock is much higher as when using a quartz based
clock.
The end of these problems should have been the so called Superclock, which uses 256 times
the word clock frequency. This equals the internal quartz frequency, so no PLL for multiplying is
needed and the clock can be used directly. But reality was different, the Superclock proved to
be much more critical than word clock. A square wave signal of 11 MHz distributed to several
devices - this simply means to fight with high frequency technology. Reflections, cable quality,
capacitive loads - at 44.1 kHz these factors may be ignored, at 11 MHz they are the end of the
clock network. Additionally it was found that a PLL not only generates jitter, but also rejects
disturbances. The slow PLL works like a filter for induced and modulated frequencies above
several kHz. As the Superclock is used without any filtering such a kind of jitter and noise suppression is missing.
The actual end of these problems is offered by the SteadyClock technology of the OctaMic
XTC. Combining the advantages of modern and fastest digital technology with analog filter techniques, re-gaining a low jitter clock signal of 22 MHz from a slow word clock of 44.1 kHz is no
problem anymore. Additionally, jitter on the input signal is highly rejected, so that even in real
world usage the re-gained clock signal is of highest quality.
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User’s Guide OctaMic XTC © RME
14.3 Cabling and Termination
Word clock signals are usually distributed in the form of a network, split with BNC T-adapters
and terminated with resistors. We recommend using off-the-shelf BNC cables to connect all
devices, as this type of cable is used for most computer networks. Actually you will find all the
necessary components (T-adapters, terminators, cables) in most electronics and computer
stores. The latter usually carries 50 Ohm components. The 75 Ohm components used for word
clock are part of video technology (RG59).
Ideally, the word clock signal is a 5 Volt square wave with the frequency of the sample rate, of
which the harmonics go up to far above 500 kHz. To avoid voltage loss and reflections, both the
cable itself and the terminating resistor at the end of the chain should have an impedance of 75
Ohm. If the voltage is too low, synchronization will fail. High frequency reflection effects can
cause both jitter and sync failure.
Unfortunately there are still many devices on the market, even newer digital mixing consoles,
which are supplied with a word clock output that can only be called unsatisfactory. If the output
breaks down to 3 Volts when terminating with 75 Ohms, you have to take into account that a
device, of which the input only works from 2.8 Volts and above, does not function correctly already after 3 meter cable length. So it is not astonishing that because of the higher voltage,
word clock networks are in some cases more stable and reliable if cables are not terminated at
all.
Ideally all outputs of word clock delivering devices are designed as low impedance types, but all
word clock inputs as high impedance types, in order to not weaken the signal on the chain. But
there are also negative examples, when the 75 Ohms are built into the device and cannot be
switched off. In this case the network load is often 2 x 75 Ohms, and the user is forced to buy a
special word clock distributor. Note that such a device is generally recommended for larger
studios.
The OctaMic XTC's word clock input can be high-impedance or terminated internally, ensuring
maximum flexibility. If termination is necessary (e.g. because the OctaMic XTC is the last device
in the chain), activate the option WCK Term. in the menu Clock.
In case the OctaMic XTC resides within a chain of devices receiving word clock, plug a Tadapter into its BNC input jack, and the cable supplying the word clock signal to one end of the
adapter. Connect the free end to the next device in the chain via a further BNC cable. The last
device in the chain should be terminated using another T-adapter and a 75 Ohm resistor (available as short BNC plug). Of course devices with internal termination do not need T-adaptor and
terminator plug.
Due to the outstanding SteadyClock technology of the OctaMic XTC, we recommend to not
pass the input signal via T-adapter, but to use the OctaMic XTC's word clock output instead.
Thanks to SteadyClock, the input signal will both be freed from jitter and - in case of loss or
drop out – be held at the last valid frequency.
15. MIDI
The OctaMic XTC has a standard MIDI input and output, a 5-pin DIN jack each. The MIDI I/O is
used for:
• remote control of the OctaMic XTC, see chapter 11.1
• transmission of MIDI data and remote control commands over MADI and USB.
User’s Guide OctaMic XTC © RME
37
User’s Guide
OctaMic XTC
Class Compliant Mode
38
User’s Guide OctaMic XTC © RME
16. General
The USB port of the OctaMic XTC provides two functions:
¾ Firmware update under Windows and Mac OS X (also see chapter 21.7)
¾ Usage as audio interface under Mac OS X and with Apple’s iPad
®
As Windows does not support Class Compliant mode with USB 2.0 directly, special support for
the OctaMic XTC has to be installed first. This is done with the RME Driver Installer for MADIface XT, MADIface USB and OctaMic XTC (Firmware Enabler). After that the XTC firmware
update tool can update the firmware to the latest version. Both tools are found on the RME
website (www.rme-audio.de
) in the section Downloads.
Under Mac OS X no preparation is required, the firmware updater is fully operational as soon as
a OctaMic XTC is connected via USB.
Thanks to native support of the Class Compliant mode the OctaMic XTC operates under Mac
OS X like an audio interface. It provides 24 channels of I/O, see chapter 18.2
Exciting as well as useful is the usage of the OctaMic XTC as hardware frontend for Apple’s
iPad. The XTC provides the iPad with the professional analog I/O connections it lacks: Superb
microphone preamps with AutoSet, professional balanced line inputs, instrument inputs, 2 hipower headphone outputs, and all common digital interface ports - ADAT, AES and MADI. All
this can be used with up to 24 channels in and out simultaneously. Everything is available fully
digital via USB, in uncompromised quality with up to 192 kHz and 24-bit. And of course a
Sysex-capable double MIDI I/O.
Note that since iOS 5 multichannel recording is supported, and since iOS 6 multichannel playback as well. At this time only djay and Auria support more than one stereo output, others are
expected to follow soon.
17. System requirements
¾ Apple computer with OS 10.6 or higher
¾ Any Apple iPad with at least iOS 5. iPhone and iPod Touch can not be used.
¾ Apple iPad Camera Connection Kit (Dock or Lightning to USB)
18. Operation
Mac Computer: Connect the XTC to the Apple Computer via USB. In the system tool Sound
and the Audio MIDI window the OctaMic XTC is now shown and can be used as record and
playback device.
iPad: Connect the USB cable to the XTC and the Camera Connection Kit. Start the iPad and
plug the Camera Connection Kit into the Dock connector. Audio playback in iTunes now automatically switches to the XTC. Use the XTC’s Digital Routing screen to assign record and playback channels to the analog and digital I/Os of the XTC.
Apps that support MIDI and are ready for Core MIDI (available since iOS 4.2) will offer dialogs
to select the desired UFX MIDI inputs and outputs.
User’s Guide OctaMic XTC © RME
39
18.1 Useful hints
When using hard covers as back panel protection for the iPad, the Connection Kit's plug may
not fit completely, causing a loose connection or partial functionality. If in doubt, remove the
cover.
No sound: Incorrect output gain settings, see chapter 8.5.1.
The iPad's volume control is inactive during USB operation!
If the XTC is not recognized:
Remove and reconnect the
Connection Kit.
Correct detection and operation of
the Connection Kit itself can be
determined in Settings / General /
About. The adapter will be listed
there right after connection, with
additional details like
manufacturer, model number etc.
Connected USB devices, i.e. the
XTC will not be shown here,
though.
Having tested several chinese replicas of the Apple Camera Connection Kit, from 2-in-1 to
5-in-1 adapters, we strongly recommend purchasing the original for use with the XTC!
All adapters seemed to work for the simple application of copying photos. Attempting to run the
XTC with USB Audio 2.0 was when the problems started. Some of the tested adapters would
not work at all, others only with short cables, and only one adapter came close to the quality of
the original. But as soon as 8-channel recording or 96 kHz playback was initiated, the Apple Kit
always performed much better.
We also recommend the purchase of a dock-to-dock extension cable, to avoid having the
CCK attached to the iPad directly with the heavy USB cable hanging down.
This can cause the CCK to slip out of the iPad’s connector, or to be in the way most of the time.
An extension cable provides enormous freedom of movement. We are working with cable
lengths of 50 cm and 1 m, both work flawlessly. These cables are available as DeLock iPhone
extension cable, or Dock Extender, e.g. from Amazon.
It is important to note that each individual component is responsible for stable operation of XTC
and iPad. As an example, a setup with an iPad connected to a 1 m DeLock cable, CCK, 5 m
USB connection to the XTC only worked with the original Apple CCK. Not only for simple iTunes
stereo playback, but also with 96 kHz playback and 8-channel recording. In this setup, the USB
cable could even be replaced with a 10 m active one. With lower quality cables or CCK replicas,
even 50 cm dock to dock to 1 m USB would be considered success...
*
*
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User’s Guide OctaMic XTC © RME
18.2 Class Compliant Mode under Windows and Mac OS X
Windows does not support USB Audio 2.0 directly. The XTC will be detected, but automatic
driver installation will fail. After installation of the special driver for the firmware updates (Firmware Enabler) the XTC will be listed as normal audio device, but is not available for WDM or
ASIO operation.
Mac OSX supports USB Audio
2.0, even with more than 2
channels.
The XTC offers 24 input and 24
output channels at up to 96 kHz,
but can also be used in a
resource saving 8-channel mode
with up to 192 kHz.
Alsa (Linux) does not work with USB 2 Class Compliant interfaces at this time, but it seems it
can be fixed (recompiled) to do so. More information is available here:
http://www.mail-archive.com/alsa-user@lists.sourceforge.net/msg28901.html
User’s Guide OctaMic XTC © RME
41
19. Supported Inputs and Outputs
In Mac OS X, either 8 or 24 channels are active, depending on the choice in the Audio MIDI
Setup. In both cases the playback signal of channels 1/2 can be copied to other outputs.
When connected to an iPad, the analog mic/line input 1 works with mono apps, inputs 1 and 2
with stereo apps (both dual mono and stereo), and up to 8 inputs with 8-channel applications
like MultiTrack DAW and Music Studio. Garage Band supports all inputs, but only two at a time.
Auria can record all 24 inputs simultaneously.
In playback operation the XTC can optionally route the iPad playback channels 1/2 to outputs
Phones 1, Phones 2, ADAT, AES and MADI (menu Digital Routing).
In slave mode (with external clock) the XTC (and with it the iPad) will be synchronized to an
external digital sample rate if there is a valid digital input signal. With a wrong sample rate
heavy audio noise will occur. Without any digital input signal the XTC stays in master mode.
The current sample rate is the one set by Mac OS X or iOS (the app in use).
While the MIDI I/Os will send and receive Sysex messages, not all apps are ready to do this.
For example MIDI Monitor and AC-7 do not support Sysex at this time. The app Midi Tool Box
can be used to verify that the UFX is working correctly, and the problem lies somewhere else.
20. Operation at the Unit
The front panel operation in Class Compliant mode is unchanged. Only the choice of sample
rate is taken over by the computer/iPad.
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User’s Guide OctaMic XTC © RME
43
User’s Guide
OctaMic XTC
Technical Reference
44
User’s Guide OctaMic XTC © RME
21. Technical Specifications
21.1 Analog
Microphone 1-8
• Input: XLR, electronically balanced
• Input impedance: 2.4 kOhm, PAD 3.5 kOhm
• Gain range: 0, +10 dB up to +65 dB in steps of 1 dB
• PAD: -20 dB
• THD @ 30 dB Gain: < -110 dB, < 0.0003 %
• THD+N @ 30 dB Gain: < -100 dB, < 0.001 %
• CMRR 50 Hz: > 60 dB
• CMRR 200 Hz – 20 kHz: > 70 dB
• Maximum input level, Gain 0 dB: +12 dBu
• Maximum input level, Gain 0 dB with PAD: +32 dBu
• Maximum input level, Gain 65 dB: -53 dBu
• Signal to Noise ratio (SNR) @ Gain 10 dB: 113 dB RMS unweighted, 117 dBA
Line TRS In 1-4
• Input: 6.3 mm TRS jack, electronically balanced
• Input impedance: 3.3 kOhm unbalanced, 6.6 kOhm balanced
• Input impedance with PAD: 3.8 kOhm unbalanced, 7.7 kOhm balanced
• Gain range: 0, +10 dB up to +65 dB in steps of 1 dB
• PAD: -18 dB
• Maximum input level, Gain 0 dB: +21 dBu
• Maximum input level, Gain 0 dB with PAD: +39 dBu
• Maximum input level, Gain 65 dB: -44 dBu
• Signal to Noise ratio (SNR) @ Gain 10 dB: 113 dB RMS unweighted, 117 dBA
Inst TRS In 5-8
• Input: 6.3 mm TS jack, unbalanced
• Input impedance: 800 kOhm (Hi-Z)
• Gain range: +10 dB up to +65 dB in steps of 1 dB
• Maximum input level, Gain 10 dB: +21 dBu
• Maximum input level, Gain 65 dB: -34 dBu
• Signal to Noise ratio (SNR) @ Gain 10 dB: 112 dB RMS unweighted, 115 dBA
Line/Phones Out 1-4
• Resolution: 24 Bit
• Noise (DR): 115 dB RMS unweighted, 118 dBA
• Frequency response @ 44.1 kHz, -0.5 dB: 9 Hz – 22 kHz
• Frequency response @ 96 kHz, -0.5 dB: 9 Hz – 45 kHz
• Frequency response @ 192 kHz, -1 dB: 8 Hz - 75 kHz
• THD+N: < -100 dB, < 0.001 %
• Channel separation: > 110 dB
• Output: 6.3 mm TRS stereo jack, unbalanced
• Maximum output level at 0 dBFS, High: +17 dBu
• Maximum output level at 0 dBFS, Low: +2 dBV
•
Output impedance: 30 Ohm
User’s Guide OctaMic XTC © RME
45
AD-Conversion General
• Resolution: 24 Bit
AD-Conversion Mic XLR
• Frequency response @ 44.1 kHz, -0.5 dB: 12 Hz – 20.8 kHz
• Frequency response @ 96 kHz, -0.5 dB: 12 Hz – 45.3 kHz
• Frequency response @ 192 kHz, -1 dB: 8 Hz - 94 kHz
• THD+N: < -100 dB, < 0.001 %
• Channel separation: > 110 dB
• Signal to Noise ratio depends on current gain setting
AD-Conversion Line/Inst TRS
• Frequency response @ 44.1 kHz, -0.5 dB: 10 Hz – 20.8 kHz
• Frequency response @ 96 kHz, -0.5 dB: 10 Hz – 45.3 kHz
• Frequency response @ 192 kHz, -1 dB: 5 Hz - 90 kHz
21.2 Digital Inputs
AES/EBU
• 1 x 25-pin D-sub, transformer-balanced, galvanically isolated, according to AES3-1992
• High-sensitivity input stage (< 0.3 Vpp)
• SPDIF compatible (IEC 60958)
• Accepts Consumer and Professional format
• Lock Range: 27 kHz – 200 kHz
• Jitter when synced to input signal: < 1 ns
• Jitter suppression: > 30 dB (2.4 kHz)
Word Clock
• BNC, not terminated (10 kOhm)
• Optional internal termination 75 Ohm
• Automatic Double/Quad Speed detection and internal conversion to Single Speed
• SteadyClock guarantees super low jitter synchronization even in varispeed operation
• Not affected by DC-offsets within the network
• Signal Adaptation Circuit: signal refresh through auto-center and hysteresis
• Overvoltage protection
• Level range: 1.0 Vpp – 5.6 Vpp
• Lock Range: 27 kHz – 200 kHz
• Jitter when synced to input signal: < 1 ns
• Jitter suppression: > 30 dB (2.4 kHz)
MADI
• Optical via FDDI duplex SC connector
• 62.5/125 and 50/125 compatible
• Accepts 56 channel and 64 channel mode, and 96k frame
• Single Wire: up to 64 channels 24 bit 48 kHz
• Double Wire / 96k frame: up to 32 channels 24 bit 96 kHz
• Quad Wire: up to 16 channels 24 bit 192 kHz
• Lock range: 28 kHz – 54 kHz
• Jitter when synced to input signal: < 1 ns
• Jitter suppression: > 30 dB (2.4 kHz)
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User’s Guide OctaMic XTC © RME
21.3 Digital Outputs
AES/EBU
• 4 x, transformer-balanced, galvanically isolated, according to AES3-1992
• Output voltage Professional 4.0 Vpp
• Format Professional according to AES3-1992 Amendment 4
• Single Wire: 4 x 2 channels 24 bit, up to 192 kHz
ADAT
• 2 x TOSLINK
• Standard: 8 channels 24 bit, up to 48 kHz
• S/MUX: 16 channels 24 bit / 48 kHz, equalling 8 channels 24 bit 96 kHz
• S/MUX4: 16 channels 24 bit / 48 kHz, equalling 4 channels 24 bit 192 kHz
Word Clock
• BNC
• Max. output voltage: 5 Vpp
• Output voltage @ 75 Ohm: 4.0 Vpp
• Impedance: 10 Ohms
• Frequency range: 27 kHz – 200 kHz
MADI
• Optical via FDDI duplex SC connector
• 62.5/125 and 50/125 compatible
• Cable length optical up to 2000 m
• Generates 56 channel and 64 channel mode, and 96k frame
• Single Wire: up to 64 channels 24 bit 48 kHz
• Double Wire / 96k frame: up to 32 channels 24 bit 96 kHz
• Quad Wire: up to 16 channels 24 bit 192 kHz
21.4 Digital
• Clocks: Internal, AES In, ADAT In, word clock In, MADI In
• Low Jitter Design: < 1 ns in PLL mode, all inputs
• Internal clock: 800 ps Jitter, Random Spread Spectrum
• Jitter suppression of external clocks: > 30 dB (2.4 kHz)
• Effective clock jitter influence on AD-conversion: near zero
• PLL ensures zero dropout, even at more than 100 ns jitter
• Supported sample rates: 28 kHz up to 200 kHz
21.5 MIDI
• 16 channels MIDI
• 5-pin DIN jacks
• Optocoupled, ground-free input
MIDI over MADI
• Invisible transmission via User bit of channel 56 (48k frame)
User’s Guide OctaMic XTC © RME
47
21.6 General
• Power supply: Internal switching PSU, 100 - 240 V AC, 30 Watts
• Typical power consumption: 14 Watts
• Maximum power consumption: < 20 Watts
• Dimensions including rack ears (WxHxD): 483 x 88 x 242 mm (19" x 3.46" x 9.5")
• Dimensions without rack ears/handles (WxHxD): 436 x 88 x 235 mm (17.2" x 3.46" x 9.3")
• Weight: 3 kg ( 6.6 lbs)
• Temperature range: +5° up to +50° Celsius (41° F up to 122°F)
• Relative humidity: < 75%, non condensing
21.7 Firmware
The OctaMic XTC is internally based on programmable logic. By re-programming of a little
component called Flash-PROM, both function and behaviour of the unit can be changed at any
time.
At the time of writing this manual, the unit is shipped with firmware 21/35. The firmware version
is displayed after power on for about one second on the display, and listed in the menu SETUP
– Options – General Settings – SW-Version.
Firmware Updates: If available then they are found on the RME website (www.rme-audio.de
) in
the section Downloads, free of charge. See chapter 16 for more details.
21.8 MADI User Bit Chart
• RS-232: channels 1 to 9 (internal through mode always active)
• ADC: channel 19
• MIDI: channel 56 (48k) / 28 (96k)
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User’s Guide OctaMic XTC © RME
21.9 Connector Pinouts
The 25 pin D-sub connector provides four AES inputs and outputs. The pinout uses the widely
spread Tascam scheme, which is also used by Digidesign.
Tascam / Digidesign:
Signal In
1/2+
In
1/2-
In
3/4+
In
3/4-
In
5/6+
In
5/6-
In
7/8+
In
7/8-
D-Sub 24 12 10 23 21 9 7 20
Signal Out
1/2+
Out
1/2-
Out
3/4+
Out
3/4-
Out
5/6+
Out
5/6-
Out
7/8+
Out
7/8-
D-Sub 18 6 4 17 15 3 1 14
GND is connected to pins 2, 5, 8, 11, 16, 19, 22, 25. Pin 13 is not connected.
The Yamaha pinout is quite popular as well. When building a D-sub to D-sub adapter or con-
nection cable, please make sure that the connectors are clearly labelled with Tascam and Ya-
maha. The cable can only be used when the Tascam side is connected to a Tascam connector,
and the Yamaha side is connected to a Yamaha connector.
Yamaha:
Signal In
1/2+
In
1/2-
In
3/4+
In
3/4-
In
5/6+
In
5/6-
In
7/8+
In
7/8-
D-Sub 1 14 2 15 3 16 4 17
Signal Out
1/2+
Out
1/2-
Out
3/4+
Out
3/4-
Out
5/6+
Out
5/6-
Out
7/8+
Out
7/8-
D-Sub 5 18 6 19 7 20 8 21
GND is connected to pins 9, 10, 11, 12, 13, 22, 23, 24, 25.
The same is true for a direct adapter cable Tascam D-sub to Euphonix D-sub.
Euphonix:
Signal In
1/2+
In
1/2-
In
3/4+
In
3/4-
In
5/6+
In
5/6-
In
7/8+
In
7/8-
D-Sub 15 2 4 16 18 5 7 19
Signal Out
1/2+
Out
1/2-
Out
3/4+
Out
3/4-
Out
5/6+
Out
5/6-
Out
7/8+
Out
7/8-
D-Sub 21 8 10 22 24 11 13 25
GND is connected to pins 3, 6, 9, 12, 14, 17, 20, 23. Pin 1 is not connected.
User’s Guide OctaMic XTC © RME
49
XLR sockets analog input 1 - 8
The XLR connectors of the analog inputs are wired according to international standards:
1 = GND (shield)
2 = + (hot)
3 = - (cold)
TRS jacks analog input 1 - 4
The stereo ¼" TRS jacks of the analog inputs are wired according to international standards:
Tip = + (hot)
Ring = – (cold)
Sleeve = GND
TS jacks analog input 5 - 8
Inputs 5 to 8 are unbalanced:
Tip = + (hot)
Ring = n.c. (not connected)
Sleeve = GND
TRS Phones jack
The analog monitor outputs on
the front are accessible
through stereo 1/4" TRS jacks.
This allows a direct connection
of headphones. In case the
output should operate as Line
output, an adapter TRS plug to
RCA phono plugs, or TRS plug
to TS plugs is required.
The pin assignment follows
international standards. The
left channel is connected to the
tip, the right channel to the ring
of the TRS jack/plug.
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22. Technical Background
22.1 Terminology
Single Speed
Sample rate range originally used in Digital Audio. Typical applications are 32 kHz (digital radio
broadcast), 44.1 kHz (CD), and 48 kHz (DAT).
Double Speed
Doubles the original sample rate range, in order to achieve higher audio quality and improved
audio processing. 64 kHz is practically never used, 88.2 kHz is quite rare in spite of certain advantages. 96 kHz is a common format. Sometimes called Double Fast.
Quad Speed
Controversially discussed way of ensuring hi-end audio quality and processing by quadrupling
the sample frequency. 128 kHz is non-existent, 176.4 kHz is rare, if at all then 192 kHz is used,
e.g. for DVD Audio.
Single Wire
Standard audio data transfer, where the audio signal's sample rate is equal to the rate of the
digital signal. Used from 32 to 192 kHz. Sometimes called Single Wide.
Double Wire
Before 1998 there were no receiver/transmitter circuits available that could receive or transmit
more than 48 kHz. Higher sample rates were transferred by splitting odd and even bits across
the L/R channels of a single AES connection. This provides for twice the data rate, and hence
twice the sample rate. A stereo signal subsequently requires two AES/EBU ports.
The Double Wire method is an industry standard today, however it has a number of different
names, like Dual AES, Double Wide, Dual Line and Wide Wire. The AES3 specification uses
the uncommon term Single channel double sampling frequency mode. When used with the
ADAT format, the term S/MUX is commonly used.
Double Wire not only works with Single Speed signals, but also with Double Speed. As an example, Pro Tools HD, whose AES receiver/transmitter only work up to 96 kHz, uses Double
Wire to transmit 192 kHz. Four channels of 96 kHz turn into two channels of 192 kHz.
Quad Wire
Similar to Double Wire, with samples of one channel spread across four channels. This way
single speed devices can transmit up to 192 kHz, but need two AES/EBU ports to transmit one
channel. Also called Quad AES.
S/MUX
Since the ADAT hardware interface is limited to Single Speed, the Double Wire method is used
for sample rates up to 96 kHz, but usually referred to as S/MUX (Sample Multiplexing). An
ADAT port supports four channels this way.
S/MUX4
The Quad Wire method allows to transmit two channels at up to 192 kHz via ADAT. The
method is referred to as S/MUX4.
Note
: All conversions of the described methods are lossless. The existing samples are just
spread or re-united between the channels.
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22.2 Lock and SyncCheck
Digital signals consist of a carrier and the data. If a digital signal is applied to an input, the receiver has to synchronize to the carrier clock in order to read the data correctly. To achieve this,
the receiver uses a PLL (Phase Locked Loop). As soon as the receiver meets the exact frequency of the incoming signal, it is locked. This Lock state remains even with small changes of
the frequency, because the PLL tracks the receiver's frequency.
If an AES or MADI signal is applied to the OctaMic XTC, the corresponding LED starts flashing.
The unit indicates LOCK, i. e. a valid input signal (in case the signal is in sync, the LED is constantly lit, see below).
Unfortunately, LOCK does not necessarily mean that the received signal is correct with respect
to the clock which processes the read out of the embedded data. Example [1]: The OctaMic
XTC is set to 44.1 kHz internal clock (clock mode master), and a mixing desk with MADI output
is connected to the XTC MADI input. The MADI LED will start flashing immediately, because the
mixing desk's sample rate is generated internally, and thus slightly higher or lower than the
XTC's internal sample rate. Result: When reading out the data, there will frequently be read
errors that cause clicks and drop outs.
Also when using multiple inputs, a simple LOCK is not sufficient. The above described problem
can be solved elegantly by setting the OctaMic XTC from internal clock to MADI In (its internal
clock will then be the clock delivered by the mixing desk). But in case another asynchronous
device is connected, there will again be a slight difference in the sample rate, and therefore
clicks and drop outs.
In order to display those problems optically at the device, the OctaMic XTC includes Sync-
Check. It checks all clocks used for synchronicity. If they are not synchronous to each other (i.
e. absolutely identical), the LED of the asynchronous input flashes. In case they are synchronous the LED stays dark, only the LED of the current clock source will be lit (constantly). In
example 1 it would have been obvious that the STATE MADI LED keeps flashing after connecting the mixing desk.
In practice, SyncCheck allows for a quick overview of the correct configuration of all digital devices. This way one of the most difficult and error-prone topics of the digital studio world finally
becomes easy to handle.
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22.3 Latency and Monitoring
The term Zero Latency Monitoring has been introduced by RME in 1998 for the DIGI96 series
and describes the ability to pass-through the computer's input signal at the interface directly to
the output. Since then, the idea behind has become one of the most important features of modern hard disk recording. In the year 2000, RME published two ground-breaking Tech Infos on
the topics Low Latency Background, which are still up-to-date: Monitoring, ZLM and ASIO, and
Buffer and Latency Jitter, found on the RME website.
How much Zero is Zero?
From a technical view there is no zero. Even the analog pass-through is subject to phase errors, equalling a delay between input and output. However, delays below certain values can
subjectively be claimed to be a zero-latency. This applies to analog routing and mixing, and in
our opinion also to RME's Zero Latency Monitoring. RME's digital receiver's buffer and the output via the transmitter cause a typical delay of 3 samples. At 44.1 kHz this equals about 68 µs
(0.000068 s), at 192 kHz only 15 µs.
Oversampling
While the delays of digital interfaces can be disregarded altogether, the analog inputs and outputs do cause a significant delay. Modern converter chips operate with 64 or 128 times oversampling plus digital filtering, in order to move the error-prone analog filters away from the audible frequency range as far as possible. This typically generates a delay of about 40 samples,
equalling one millisecond. A playback and re-record of the same signal via DA and AD (loopback) then causes an offset of the newly recorded track of about 2 ms.
Low Latency!
The OctaMic XTC uses latest AD-converters with special low latency filters, exceptional Signal
to Noise ratio, lowest distortion figures and lightning quick conversion. A delay of only 10 samples hasn’t been available just a few years back. But even the chip used for DA-conversion has
a lower delay than usual. The exact delays caused by the AD-conversion of the OctaMic XTC
are:
Sample frequency kHz 44.1 48 88.2 96 176.4 192
AD (12.6 x 1/fs) ms 0.28 0.26 0.14 0.13
AD (9.8 x 1/fs) ms 0.06 0.05
DA (28 x 1/fs) ms 0.63 0.58 0.32 0.29 0.16 0.15
These values are smaller than those available from even much more expensive devices. They
represent an important step in further reducing the latency in the computer-based recording
studio.
User’s Guide OctaMic XTC © RME
53
22.4 DS - Double Speed
When activating the Double Speed mode the OctaMic XTC operates at double sample rate. The
internal clock 44.1 kHz turns to 88.2 kHz, 48 kHz to 96 kHz. The internal resolution is still 24 bit.
Sample rates above 48 kHz were not always taken for granted, and are still not widely used
because of the CD format (44.1 kHz) dominating everything. Before 1998 there were no receiver/transmitter circuits available that could receive or transmit more than 48 kHz. Therefore a
work-around was used: instead of two channels, one AES line only carries one channel, whose
odd and even samples are being distributed to the former left and right channels. By this, you
get the double amount of data, i. e. also double sample rate. Of course in order to transmit a
stereo signal two AES/EBU ports are necessary then.
This transmission mode is called Double Wire in the professional studio world, and is also
known as S/MUX (Sample Multiplexing) in connection with the ADAT format.
Not before February 1998, Crystal shipped the first 'single wire' receiver/transmitters that could
also work with double sample rate. It was then possible to transmit two channels of 96 kHz data
via one AES/EBU port.
But Double Wire is still far from being dead. On one hand, there are still many devices which
can't handle more than 48 kHz, e. g. digital tape recorders. But also other common interfaces
like ADAT or TDIF are still using this technique.
Because the ADAT interface does not allow for sampling frequencies above 48 kHz (a limitation
of the interface hardware), the OctaMic XTC automatically uses Sample Multiplexing in DS
mode. One channel's data is distributed to two channels according to the following table:
Original 1 2 3 4 5 6 7 8
DS Signal
Port
1/2
1
3/4
1
5/6
1
7/8
1
1/2
2
3/4
2
5/6
2
7/8
2
As the transmission of double rate signals is done at standard sample rate (Single Speed), the
ADAT outputs still deliver 44.1 kHz or 48 kHz.
22.5 QS – Quad Speed
Due to the small number of available devices that use sample rates up to 192 kHz, but even
more due to a missing real world application (CD...), Quad Speed has had no broad success so
far. An implementation of the ADAT format as double S/MUX (S/MUX4) results in only two
channels per optical output. Therefore in Quad Speed mode the OctaMic XTC is limited to 4
channels at the ADAT outputs.
The AES outputs provide 192 kHz as Single Wire only.
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User’s Guide OctaMic XTC © RME
22.6 AES/EBU - SPDIF
The most important electrical properties of 'AES' and 'SPDIF' can be seen in the table below.
AES/EBU is the professional balanced connection using XLR plugs. The standard is being set
by the Audio Engineering Society based on the AES3-1992. For the 'home user', SONY and
Philips have omitted the balanced connection and use either Phono plugs or optical cables
(TOSLINK). The format called S/P-DIF (SONY/Philips Digital Interface) is described by IEC
60958.
Type AES3-1992 IEC 60958
Connection XLR RCA / Optical
Mode Balanced Unbalanced
Impedance 110 Ohm 75 Ohm
Level 0.2 V up to 5 Vpp 0.2 V up to 0.5 Vpp
Clock accuracy not specified
I: ± 50 ppm
II: 0.1%
III: Variable Pitch
Jitter < 0.025 UI (4.4 ns @ 44.1 kHz) not specified
Besides the electrical differences, both formats also have a slightly different setup. The two
formats are compatible in principle, because the audio information is stored in the same place in
the data stream. However, there are blocks of additional information, which are different for both
standards. In the table, the meaning of the first byte (#0) is shown for both formats. The first bit
already determines whether the following bits should be read as Professional or Consumer
information.
Byte Mode Bit 0 1 2 3 4 5 6 7
0 Pro P/C Audio? Emphasis Locked Sample Freq.
0 Con P/C Audio? Copy Emphasis Mode
It becomes obvious that the meaning of the following bits differs quite substantially between the
two formats. If a device like a common DAT recorder only has an SPDIF input, it usually understands only this format. In most cases, it will switch off when being fed Professional-coded data.
The table shows that a Professional-coded signal would lead to malfunctions for copy prohibition and emphasis, if being read as Consumer-coded data.
Nowadays many devices with SPDIF input can handle Professional subcode. Devices with
AES3 input almost always accept Consumer SPDIF (passive cable adapter required).
User’s Guide OctaMic XTC © RME
55
22.7 Signal to Noise Ratio in DS- / QS-Operation
The outstanding signal to noise ratio of the OctaMic XTC's AD-converters can be verified even
without expensive test equipment, by using record level meters of various software. But when
activating the DS and QS mode, the displayed noise level will rise from -113 dBFS to -106
dBFS at 96 kHz, and –79 dBFS at 192 kHz. This is not a failure. The software measures the
noise of the whole frequency range, at 96 kHz from 0 Hz to 48 kHz (RMS unweighted), at 192
kHz from 0 Hz to 96 kHz.
When limiting the measurement range from 20 Hz to 20 kHz (so called audio bandpass) the
value would be -113 dB again. This can be verified with RME's DIGICheck. The function Bit
Statistic & Noise measures the noise floor by Limited Bandwidth, ignoring DC and ultrasound.
The reason for this behaviour is the noise shaping technology of the analog to digital converters. They move all noise and distortion to the in-audible higher frequency range, above 30 kHz.
That’s how they achieve their outstanding performance and sonic clarity. Therefore the noise is
slightly increased in the ultrasound area. High-frequent noise has a high energy. Add the quadrupled bandwidth, and a wideband measurement will show a significant drop in SNR, while the
human ear will notice absolutely no change in the audible noise floor.
As can be seen in the above picture, the noise floor stays fully unchanged up to 30 kHz. With
sample rates up to 96 kHz the noise shaping happens outside of the transmission range.
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User’s Guide OctaMic XTC © RME
22.8 MADI Basics
MADI, the serial Multichannel Audio Digital Interface, has been defined already in 1989 as an
extension of the existing AES3 standard following several manufacturers' wish. The format also
known as AES/EBU, a balanced bi-phase signal, is limited to two channels. Simply put, MADI
contains 28 of those AES/EBU signals in serial, i. e. after one another, and the sample rate can
still even vary by +/-12.5%. The limit which cannot be exceeded is a data rate of 100Mbit/s.
Because an exact sampling frequency is used in most cases, the 64 channel mode was introduced officially in 2001. It allows for a maximum sample rate of 48 kHz + ca. 1%, corresponding
to 32 channels at 96 kHz, without exceeding the maximum data rate of 100 Mbit/s. The effective
data rate of the port is 125 Mbit/s due to additional coding.
Older devices understand and generate only the 56 channel format. Newer devices often work
in the 64 channel format, but offer still no more than 56 audio channels. The rest is being eaten
up by control commands for mixer settings etc.. The OctaMic XTC shows that this can be done
in a much better way, with an invisible transmission of 16 MIDI channels plus serial RS232 data
stream, and the 64-channel MADI signal still being 100% compatible.
For the transmission of the MADI signal, proved methods known from network technology were
applied. Most people know unbalanced (coaxial) cables with 75 Ohms BNC plugs, they are not
expensive and easy to get. The optical interface is much more interesting due to its complete
galvanic separation, but for many users it is a mystery, because very few have ever dealt with
huge cabinets full of professional network technology. Therefore here are some explanations
regarding 'MADI optical'.
• The cables used are standard in computer network technology. They are thus not at all
expensive, but unfortunately not available in every computer store.
• The cables have an internal fibre of only 50 or 62.5 µm diameter and a coating of 125 µm.
They are called network cables 62.5/125 or 50/125, the former mostly being blue and the latter mostly being orange. Although in many cases not clearly labelled, these are always (!)
glass fibre cables. Plastic fibre cables (POF, plastic optical fibre) can not be manufactured in
such small diameters.
• The plugs used are also an industry standard and called SC. Please don't mix them up with
ST connectors, which look similar to BNC connectors and are being screwed. Plugs used in
the past (MIC/R) were unnecessarily big and are not being used any longer.
• The cables are available as a duplex variant (2 cables being glued together) or as a simplex
variant (1 cable). The OctaMic XTC’s opto module supports both variants.
• The transmission uses the multimode technique which supports cable lengths of up to al-
most 2 km. Single mode allows for much longer distances, but it uses a completely different
fibre (8 µm). By the way, due to the wave-length of the light being used (1300 nm), the optical signal is invisible to the human eye.
User’s Guide OctaMic XTC © RME
57
22.10 SteadyClock
The SteadyClock technology of the OctaMic XTC guarantees an excellent performance in all
clock modes. Its highly efficient jitter suppression refreshes and cleans up any clock signal, and
provides it as reference clock at the word clock output.
Usually a clock section consists of an analog PLL for external synchronization and several
quartz oscillators for internal synchronisation. SteadyClock requires only one quartz, using a
frequency not equalling digital audio. Latest circuit designs like hi-speed digital synthesizer,
digital PLL, 100 MHz sample rate and analog filtering allow RME to realize a completely newly
developed clock technology, right within the FPGA at lowest costs. The clock's performance
exceeds even professional expectations. Despite its remarkable features, SteadyClock reacts
quite fast compared to other techniques. It locks in fractions of a second to the input signal,
follows even extreme varipitch changes with phase accuracy, and locks directly within a range
of 28 kHz up to 200 kHz.
SteadyClock has originally been developed to gain a stable and clean
clock from the heavily jittery MADI data
signal. The embedded MADI clock
suffers from about 80 ns jitter, caused
by the time resolution of 125 MHz
within the format. Common jitter values
for other devices are 5 ns, while a very
good clock will have less than 2 ns.
The picture to the right shows the
MADI input signal with 80 ns of jitter
(top graph, yellow). Thanks to SteadyClock this signal turns into a clock with
less than 2 ns jitter (lower graph, blue).
Using the other input sources of the
OctaMic XTC, word clock, ADAT and
and AES/EBU, you'll most probably
never experience such high jitter
values. But SteadyClock is not only
ready for them, it would handle them
just on the fly.
The screenshot to the right shows an
extremely jittery word clock signal of
about 50 ns jitter (top graph, yellow).
Again SteadyClock provides an extreme clean-up. The filtered clock
shows less than 2 ns jitter (lower
graph, blue).
The cleaned and jitter-freed signal can be used as reference clock for any application, without
any problem. The signal processed by SteadyClock is of course not only used internally, but
also available at the XTC’s word clock output. It is also used to clock the digital outputs MADI,
ADAT and AES/EBU.
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User’s Guide OctaMic XTC © RME
23. Block Diagram
User’s Guide OctaMic XTC © RME
59
24. MIDI Implementation OctaMic XTC
24.1 Basic SysEx Format
Value
Name
F0h SysEx header
00h 20h 0Dh MIDITEMP manufacturer ID
69h Model ID (OctaMic XTC)
00h..7Eh, 7Fh MIDI device ID
mm Command ID
nn Data (parameter index, parameter LSB, parameter MSB, set-flags, ...)
F7h EOX
24.2 Message Types - Commands
Value Name
10h Request value
11h Request level meter data
012h Request changed parameters
020h Set parameter (multiple parameters allowed)
30h Send parameters (multiple parameters allowed)
Request Value
Format: F0 00 20 0D 69 (dev ID) 10 F7
This string triggers a complete dump of all parameter data bytes.
Value Response
After being triggered by receiving a request parameter command, device sends a string of all
parameter data bytes. Message type is set to 30h.
Set Parameter
Sets any number of parameters.
mm / nn can be repeated freely.
Request Level Meter Data
Format: F0 00 20 0D 69 (dev ID) 11 F7
This string triggers a dump of the level meter data.
0xf0, 0x00, 0x20, 0x0d, 0x69
MIDI device ID, command ID, parameter index, parameter LSB, parameter MSB, set-flags, ...,
0xf7
(… = multiple parameters per message allowed, each consisting of index, LSB, MSB, set-flags)
Set-flags: set to value from list to set the according parameter in the device, otherwise parame-
ter will be ignored. Set-flags are only assigned for commands containing multiple parameters.
Messages sent by the device (command ID 0x30) do not contain set-flags.
Example for MIDI device ID 0
f0 00 20 0 69 00 20 01 1c 08 7f 0a 30 10 0d f7
Set Gain Mic 2 to 37dB; Pad on; Phase-Invert, Mute, AutoSet, 48V off; all parameters to be set.
Set Phones 1 source to MADI1/2; high Level, Phase-Invert off, Mute not to be set.
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User’s Guide OctaMic XTC © RME
24.3 Table
Commands
ID Command
Send Rec
0x10 request all parameters x
0x11 request level data x
0x12
request changed parameters (in case of no changes: emp-
ty block) x
0x20 set parameter (multiple parameters allowed) x
0x30 send parameters (multiple parameters possible) x
Parameters
Index Value
Send Rec Flag
0
Channel Settings Mic 1 (see Details below) x x s.d.
1
Channel Settings Mic 2 x x s.d.
2
Channel Settings Mic 3 x x s.d.
3
Channel Settings Mic 4 x x s.d.
4
Channel Settings Mic 5 x x s.d.
5
Channel Settings Mic 6 x x s.d.
6
Channel Settings Mic 7 x x s.d.
7
Channel Settings Mic 8 x x s.d.
8
Phones 1 Volume (see Details below) x x n.a.
9
Phones 1 Balance x x n.a.
10
Phones 1 Settings x x s.d.
11
Phones 2 Volume x x n.a.
12
Phones 2 Balance x x n.a.
13
Phones 2 Settings x x s.d.
14
Digital Routing ADAT Out, ADAT2 Out (see Details below) x x s.d.
15
Digital Routing AES Out x x s.d.
16
Digital Routing MADI 1-8, MADI 9-16 x x s.d.
17
Digital Routing MADI 17-24, MADI 25-32 x x s.d.
18
Digital Routing MADI 33-40, MADI 41-48 x x s.d.
19
Digital Routing MADI 49-56, MADI 57-64 x x s.d.
20
Digital Routing Rec. 9-16, Rec. 17-24 x x s.d.
21
Clock Settings x x
LSB
Bit 0-3: Clock Sourc (internal, WCK, AES1..AES4, ADAT,
MADI) 0x01
Bit 4: WCK always single 0x02
Bit 5: WCK termination active 0x04
MSB
Bit 0-3: Samplerate index (32k, 44.1k, 48k, 64k, 88.2k, 96k,
128k, 176.4k, 192k) 0x08
22
MADI Settings
LSB
Bit 0-1: Delay Compensation (0-Off, 1-Manual, 2-Auto-ID,
3-Auto CA) x x 0x01
LSB Bit 2: MADI-Format (0: 56ch, 1: 64ch) x x 0x02
LSB Bit 3: MADI-Frame (0: 96k, 1: 48k) x x 0x04
MSB Bit 0-2: Delay Compensation ID (0-7 for ID 1-8) x x 0x08
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61
23
MIDI Source Select x x
LSB Bit 0-2: Source USB1 Output (see Value Table 2) 0x01
Bit 3-6: Source USB2 Output (see Value Table 2) 0x02
MSB Bit 0-2: Source DIN Output (see Value Table 2) 0x04
Bit 3-6: Source MIDI over MADI (see Value Table 2) 0x08
24
Group Enable x x
LSB Bit 0-3: Group 1..4 enable (ON) n.a.
MSB Bit 0-3: Group 1..4 AutoSet (AS) n.a.
25
Save/Load Preset (Receive only) x
LSB Load Preset 1..6, 0 for no operation n.a.
MSB Save Preset 1..6, 0 for no operation n.a.
Level Meter data
26
Level Meter Mic 1 / 2 (see details below) x n.a.
27
Level Meter Mic 3 / 4 x n.a.
28
Level Meter Mic 5 / 6 x n.a.
29
Level Meter Mic 7 / 8 x n.a.
30
Level Meter Phones 1 x n.a.
31
Level Meter Phones 2 x n.a.
Details
Channel Settings Mic
Flag
LSB Bit 0-5 Gain (0: 0dB, 1: 10dB...56:65dB) 0x01
Bit 6: Phase Invert 0x02
MSB Bit 0: Mute 0x04
Bit 1: AutoSet 0x08
Bit 2: +48V 0x10
Bit 3: Pad (Channel 1-4)/Instrument (Channel 5-8) 0x20
Bit 4-6: Group (0: off, 1..4: group) 0x40
Phones Volume
LSB Bit 0-3: 1/10 dB of Volume[dB]+65.0 n.a.
MSB integer part of Volume[dB]+65.0 (0...71 for -65...+6dB)
Phones Balance
LSB 1/100 Balance n.a.
MSB Bit 0: Left (1) / Right (0)
Phones Settings
LSB Source Bit 0..6 0x01
MSB Bit 0: Bit 7 Source (see Value Table 1)
Bit 1: Mute 0x02
Bit 2-3: Phase Invert (0: off, 1: both, 2: left, 3: right) 0x04
Bit 4: Level (0: Low, 1: High) 0x08
Digital Routing
LSB Bit 0-3: Source 1 (see Value Table 2) 0x01
MSB Bit 0-3: Source 2 (see Value Table 2) 0x02
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User’s Guide OctaMic XTC © RME
Level Meter (Send only)
LSB Channel 1
MSB Channel 2
Value 126: OVR
125..95: 0dB..-6dB (p[dB] = (Value – 95) * 0.2)
94...23: -6.5dB..-42dB (p[dB] = (Value – 107) * 0.5)
22..1: -43..-64dB (p[dB] = Value – 65)
0: underflow
Abbreviations
n.a. not assigned
s.d. see details
Value Table 1 – Phones Sources
0 1 2 3 4 5 6 7
0.. Play 1/2 Play 3/4 Mic 1 Mic 2 Mic 3 Mic 4 Mic 5 Mic 6
8.. Mic 7 Mic 8 Mic 1/2 Mic 3/4 Mic 5/6 Mic 7/8 Mic 1-8 Mic 1-8S
16.. ADAT 1 ADAT 2 ADAT 3 ADAT 4 ADAT 5 ADAT 6 ADAT 7 ADAT 8
24.. ADAT 1/2 ADAT 3/4 ADAT 5/6 ADAT 7/8 AES 1 AES 2 AES 3 AES 4
32.. AES 5 AES 6 AES 7 AES 8 AES 1/2 AES 3/4 AES 5/6 AES 7/8
40.. MADI 1 MADI 2 MADI 3 MADI 4 MADI 5 MADI 6 MADI 7 MADI 8
48.. MADI 1/2 MADI 3/4 MADI 5/6 MADI 7/8 MADI 9 MADI 10 MADI 11 MADI 12
56.. MADI 13 MADI 14 MADI 15 MADI 16 MADI 9/10 MA 11/12 MA 13/14 MA 15/16
64.. MADI 17 MADI 18 MADI 19 MADI 20 MADI 21 MADI 22 MADI 23 MADI 24
72.. MA 17/18 MA 19/20 MA 21/22 MA 23/24 MADI 25 MADI 26 MADI 27 MADI 28
80.. MADI 29 MADI 30 MADI 31 MADI 32 MA 25/26 MA 27/28 MA 29/30 MA 31/32
88.. MADI 33 MADI 34 MADI 35 MADI 36 MADI 37 MADI 38 MADI 39 MADI 40
96.. MA 33/34 MA 35/36 MA 37/38 MA 39/40 MADI 41 MADI 42 MADI 43 MADI 44
104.. MADI 45 MADI 46 MADI 47 MADI 48 MA 41/42 MA 43/44 MA 45/46 MA 47/48
112.. MADI 49 MADI 50 MADI 51 MADI 52 MADI 53 MADI 54 MADI 55 MADI 56
120.. MA 49/50 MA 51/52 MA 53/54 MA 55/56 MADI 57 MADI 58 MADI 59 MADI 60
128.. MADI 61 MADI 62 MADI 63 MADI 64 MA 57/58 MA 59/60 MA 61/62 MA 63/64
Value Table 2 – Digital Routing Sources
0 1 2 3 4 5 6 7
0.. Mic 1-8 ADAT IN AES IN M 1-8 M 9-16 M 17-24 M 25-32 M 33-40
8.. M 41-48 M 49-56 M 57-64 PB 1-8 PB 5-12 PB 9-16 PB13-20 PB17-24
Value Table 3 – MIDI Sources
0 1 2 3 4 5
OFF USB1 USB2
MADI
In DIN in Control
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