User's Guide Hammerfall® DSP System Digiface TotalMix ™ 24 Bit / 96 kHz ü ® SyncAlign ® ZLM ® SyncCheck PCI Busmaster Digital I/O System PCI and CardBus Interface 2 + 24 Channels SPDIF / ADAT Interface 24 Bit / 96 kHz Analog Stereo Monitor ADAT Sync In MIDI I/O
General 1 2 3 4 5 6 7 8 9 Introduction............................................................ 6 Package Contents .................................................. 6 System Requirements............................................ 6 Brief Description and Characteristics................... 7 Hardware Installation 5.1 PCI Interface ........................................................ 7 5.2 CardBus Card....................................................... 7 5.3 Notes on Power Supply ..............
Driver Installation and Operation - Mac OS X 19 Driver and Flash Update 19.1 Driver Installation .............................................. 33 19.2 Driver Update .................................................... 33 19.3 Flash Update ..................................................... 33 20 Configuring the Digiface 20.1 Settings Dialog .................................................. 34 20.2 Clock Modes – Synchronization......................... 36 21 Mac OS X FAQ 21.
29 TotalMix: The Matrix 29.1 Overview............................................................62 29.2 Elements of the Matrix View...............................62 29.3 Operation ...........................................................62 29.4 Advantages of the Matrix....................................63 30 TotalMix Super-Features 30.1 ASIO Direct Monitoring (Windows only)..............63 30.2 Selection and Group based Operation ................64 30.3 Copy Routings to other Channels .................
User's Guide Digiface General User's Guide HDSP System Digiface © RME 5
1. Introduction Thank you for choosing the RME Hammerfall DSP system. This unique audio system is capable of transferring analog and digital audio data directly to a computer from practically any device. The latest Plug and Play technology guarantees a simple installation, even for the inexperienced user. The numerous unique features and well thought-out configuration dialog puts the Hammerfall DSP at the very top of the range of computer-based audio interfaces.
4. Brief Description and Characteristics • • • • • • • • • • • • • • • • • Hammerfall design: 0% (zero!) CPU load, even using all 52 ASIO channels All settings can be changed in real-time Analog, ADAT and SPDIF I/Os can be used simultaneously 8 buffer sizes/latencies available: 1.
5.3 Notes on Power Supply • The CardBus card delivers no power to the Digiface. Therefore a hi-tech switching power supply is included. • The PCI card operates as power supply for the attached Digiface via the FireWire cable. An external power supply is not required. The Digiface draws a high startup current of more than 2.5 A during initialisation. Current at 12 Volt operating voltage: unloaded 200 mA (2.5 Watts), loaded 400 mA (4.8 Watts). Supply voltage range DC 8 V – 28 V, AC 8 V – 20 V. 6.
6.2 Quick Start After the driver installation (see chapter 10 / 19) connect the digital inputs and outputs to your other digital equipment. The Digiface's digital outputs provide SPDIF (AES/EBU compatible) and ADAT optical signals at the corresponding ports. An analog stereo output is available on the front. This output is a very low impedance type, which can also be used to connect headphones. 6.3 Notes on Laptops and CardBus The HDSP system uses the notebook’s PCMCIA type II port as CardBus interface.
7. Accessories RME offers several optional accessories. Also parts of the HDSP system are available separately. Part Number 36000 Description 19“, 1UH Universal rack holder This 19" rack holder has holes for Digiface and Digiface. Two units can be installed side by side in any combination. The rack holder also includes holes for nearly all 19" half-rack units from other manufacturers. 36001 36002 36005 36010 Firewire cable IEEE1394 6M/6M, 1 m (3.3 ft) Firewire cable IEEE1394 6M/6M, 3 m (9.
8. Warranty Each individual Hammerfall DSP undergoes comprehensive quality control and a complete test at RME before shipping. The usage of high grade components allow us to offer a full two year warranty. We accept a copy of the sales receipt as valid warranty legitimation. If you suspect that your product is faulty, please contact your local retailer.
CE / FCC Compliance Statements CE This device has been tested and found to comply with the EN55022 class B and EN50082-1 norms for digital devices, according to the European Council directive on counterpart laws in the member states relating to electromagnetic compatibility (EMVG). FCC This device has been tested and found to comply with the requirements listed in FCC Regulations, part 15 for Class ‘B’ digital devices.
User's Guide Digiface Driver Installation and Operation - Windows User's Guide HDSP System Digiface © RME 13
10. Driver and Firmware 10.1 Driver Installation After the interface has been installed correctly, connected to the Digiface (see 5. Hardware Installation), and the computer has been switched on, Windows will recognize the new hardware component and start its ‘Hardware Wizard’. Insert the RME Driver CD into your CD-ROM drive, and follow further instructions which appear on your computer screen. The driver files are located in the directory \HDSP_w2k on the RME Driver CD.
10.4 Firmware Update The Flash Update Tool updates HDSP PCI cards or CardBus cards to the latest version. It requires an already installed driver. Start the program hdsp_fut.exe. The Flash Update Tool displays the current revision of the HDSP interface, and whether it needs an update or not. If so, then please manually select if a PCI card (desktop computer) or a CardBus card (laptop) shall be flashed. Next simply press the 'Update' button. A progress bar will indicate when the flash process is finished.
11. Configuring the Digiface 11.1 Settings Dialog Configuration of the HDSP system Digiface is done via its own settings dialog.
MME Check Input verifies the current digital input signal against the settings in the record program. When de-activated a recording will always be allowed, even with non-valid input signals. Check Input is valid for MME only. SyncAlign guarantees synchronous channels when using MME multitrack software. This option should only be switched off in case the used software does not work correctly with SyncAlign activated.
I/O Box State This field displays the current state of the I/O-box. Error: I/O-box not connected or missing power Detected: The interface has found an I/O-box and tries to load the firmware Connected: Communication between interface and I/O-box operates correctly Disconnected: Communication between interface and I/O-box has been interrupted, I/Obox continues operation Word Clock Out The word clock output signal usually equals the current sample rate.
The Hammerfall DSP's ADAT optical input and the SPDIF input operate simultaneously. Because there is no input selector however, the HDSP has to be told which of the signals is the sync reference (a digital device can only be clocked from a single source). This is why the system has been equipped with automatic clock source selection, which adopts the first available input with a valid digital signal as the clock reference input.
An example to illustrate this: The ADAT1 and ADAT2 inputs are receiving signals from a digital mixing desk that has been set to clock mode 'Internal' or 'Master'. An ADAT recorder is connected to input ADAT3. The Hammerfall DSP is set to AutoSync mode. As expected, SyncCheck shows that the ADAT1 and ADAT2 inputs are in sync (as they are driven by the same clock from the mixing desk), but shows ‘Lock’ instead of 'Sync' for the input ADAT3.
12. Operation and Usage 12.1 Playback The HDSP system can play back audio data only in supported modes (channels, PCM) and formats (sample rate, bit resolution). Otherwise an error message appears (for example at 22 kHz and 8 bit). In the audio application being used, HDSP must be selected as output device. This can often be found in the Options, Preferences or Settings menus under Playback Device, Audio Devices, Audio etc. We strongly recommend switching off all system sounds (via >Control Panel /Sounds<).
12.2 DVD-Playback (AC-3/DTS) under MME AC-3 / DTS When using popular DVD software player like WinDVD and PowerDVD, their audio data stream can be sent to any AC-3/DTS capable receiver, using the Hammerfall DSP's SPDIF output. For this to work the SPDIF output wave device has to be selected in >Control Panel/ Sounds and Multimedia/ Audio<. Also check 'use preferred device only'. You will notice that the DVD software's audio properties now allow to use 'SPDIF Out', 'Use SPDIF' or to 'activate SPDIF output'.
12.3 Low Latency under MME (Buffer Size Adjustment) Using Windows 95 or 98 the MME buffer size was nothing to worry about. Latencies below 46 ms were not possible. Meanwhile both computers and operating system have become much more powerful, and since Windows ME/2000/XP latencies far lower can be used. SAWStudio and Sonar allowed to use such low settings from the start. Sequoia was updated in version 5.91, WaveLab in version 3.04.
12.5 Digital Recording Unlike analog soundcards which produce empty wave files (or noise) when no input signal is present, digital I/O cards always need a valid input signal to start recording. To take this into account, RME has included three unique features in the Hammerfall DSP system: a comprehensive I/O signal status display (showing sample frequency, lock and sync status) in the Settings dialog, status LEDs for each input, and the protective Check Input function.
13. Operation under ASIO 2.0 13.1 General Start the ASIO software and select ASIO Hammerfall DSP as the audio I/O device. The 'ASIO system control' button opens the HDSP's Settings dialog (see chapter 10 / 20, Configuration). Hammerfall DSP supports ASIO Direct Monitoring (ADM). Please note that currently Nuendo, Cubase and Logic either do not support ADM completely or error-free. Using emulated MIDI drivers often causes a drift and delay between audio and MIDI.
13.3 Synchronization To achieve sample-accuracy between the ADAT recorder and Hammerfall DSP while running Cubase, connect the ADAT sync output with the 9-pin D-type sync input of the HDSP. The ‘Time Code’ field in the Settings dialogue should now show the same position as the ADAT recorder. Double-clicking on the Sync button in Cubase’s transport panel will open the ‘Synchronization’ dialog. Select ASIO 2.
14. Operation under GSIF (Gigasampler Interface) Windows 2000/XP The GSIF interface of the Hammerfall DSP allows direct operation with Gigastudio, with up to 26 channels, 96 kHz and 24 bit. The new GSIF 2.0 is also supported with both audio and MIDI. Gigastudio requires a lot of the computer’s calculation power. An optimum performance is achieved with a stand-alone GSIF PC. However, when using the Hammerfall DSP, the latency is always the same as the one selected for ASIO operation.
16. DIGICheck The DIGICheck software is a unique utility developed for testing, measuring and analysing digital audio streams. Although this Windows software is fairly self-explanatory, it still includes a comprehensive online help. DIGICheck 4.4 operates as multi-client ASIO host, therefore can be used in parallel to any software, be it MME, ASIO or GSIF, with both inputs and outputs (!). The following is a short summary of the currently available functions: • Level Meter.
Playback works, but record doesn’t • Check that there is a valid signal at the input. If so, the current sample frequency is displayed in the Settings dialog. • Check whether the HDSP system has been selected as recording device in the audio application. • Check whether the sample frequency set in the audio application (‘Recording properties’ or similar) matches the input signal. • Check that cables/devices have not been connected in a closed loop. If so, set the systems’s clock mode to Master.
18. Diagrams 18.1 Channel Routing ASIO at 96 kHz This diagram shows the signal paths in ASIO double speed mode (88.2 / 96 kHz). The devices available via the ASIO driver have been designed to avoid conflicts in normal operation. Record and playback are identical.
18.2 Channel Routing MME at 96 kHz This diagram shows the signal paths in MME double speed mode (88.2 / 96 kHz). The devices available via the MME wave driver have been designed to avoid conflicts in normal operation, which is why channels 5, 6, 7 and 8 of the ADAT device have been omitted. Record and playback are identical.
User's Guide Digiface Driver Installation and Operation – Mac OS X 32 User's Guide HDSP System Digiface © RME
19. Driver and Flash Update 19.1 Driver Installation First fit the card (see 5. Hardware Installation), then switch on the computer and install the drivers from the RME Driver CD. The driver file is located in the folder Hammerfall DSP. Installation works automatically by a double-click on the file hdsp.mpkg. RME recommends to download the latest driver version from the RME website! If done, the procedure is as follows: Double-click onto hdsp_xx.gz to expand the archive file to hdsp_xx.
All other PCI cards, and CardBus with 15-pin flat connector When the update fails (status: failure) the flash process should be repeated several times, until no error message occurs anymore. If the failure message is displayed nonetheless, the interface will most propably no longer work when the computer is switched off and on again. The interface then has to be re-programmed at the factory. We have invested a lot of work to prevent the system from getting in this state.
SPDIF In Defines the input for the SPDIF signal. 'Coaxial' relates to the RCA socket, 'ADAT1' to the optical TOSLINK input. SPDIF Out The SPDIF output signal is constantly available at the phono plug. After selecting 'ADAT1' it is also routed to the optical TOSLINK output. For further details about the settings ‘Professional’, ‘Emphasis’ and ‘Non-Audio’, please refer to chapter 26.2. SPDIF Freq. Displays the sample rate of the signal at the SPDIF input.
System Clock Shows the current clock state of the HDSP system. The system is either Master (using its own clock) or Slave (see AutoSync Ref). SyncCheck SyncCheck indicates whether there is a valid signal (Lock, No Lock) for each input (Word Clock, ADAT1-3, ADAT Sync, SPDIF), or if there is a valid and synchronous signal (Sync). The AutoSync Reference display shows the input and frequency of the current sync source. 20.
RME’s exclusive SyncCheck technology (first implemented in the Hammerfall) enables an easy to use check and display of the current clock status. The ‘SyncCheck’ field indicates whether no signal (‘No Lock’), a valid signal (‘Lock’) or a valid and synchronous signal (‘Sync’) is present at each of the digital clock source inputs. The AutoSync Reference display shows the current sync source and the measured frequency.
21. Mac OS X FAQ 21.1 Round about Driver Installation The driver with the file suffix gz provided by RME is a compressed TAR archive. TAR bundles multiple files and folders into one file, but does not save memory space nor download time. Both TAR and gz are supported natively by OS X, a double click on the file is all you need to do. Older browsers do not recognize gz as an archive, loading the file as a document. This results in a cryptic looking text within the browser window.
21.3 Supported Sample Rates RME's Mac OS X driver supports all sampling frequencies provided by the hardware. Besides 96 kHz this also includes 32 kHz and 64 kHz. But not every software will support all the hardware's sample rates. For example Spark does not display 32 kHz and 64 kHz. The hardware's capabilities can easily be verified in the Audio MIDI Setup. Select Audio devices under Properties of: and choose the Hammerfall DSP. A click on Format will list the supported sample frequencies.
Multicard Operation OS X supports more than one audio device. Their simultaneous usage within one program had been limited to Motu's Digital Performer until 10.3.9. Since 10.4 (Tiger) Core Audio offers the function Aggregate Devices, which allows to combine several devices into one, so that a multi-device operation is now possible with any software. The Hammerfall DSP driver adds a number to each unit, so they are fully accessible in any multicard-capable software. 22.
23. Diagram: Channel Routing at 96 kHz This diagram shows the signal paths in double speed mode (88.2 / 96 kHz). The last four channels of the ADAT port have no function anymore in Core Audio, but are used by the hardware to transmit data at double sample rate.
User's Guide HDSP System Digiface © RME
User's Guide Digiface Disconnect Mode, Connections and TotalMix User's Guide HDSP System Digiface © RME 43
24. Disconnect Mode RME's exclusive Disconnect mode lets you adjust level, input selection and signal mix via your computer, and simply detach the Digiface afterwards. With this, a stand-alone operation of the Digiface gets possible. When the Digiface has been configured using Settingsdialog and TotalMix, it won't loose those settings after detaching it from the computer.
26. Digital Connections 26.1 ADAT The ADAT optical input of the HDSP system is fully compatible with all ADAT optical outputs. RME's unsurpassed Bitclock PLL prevents clicks and drop outs even in extreme varipitch operation, and guarantees a fast and low jitter lock to the digital input signal. A usual TOSLINK cable is sufficient for connection. More information on Double Speed (S/MUX) can be found in chapter 34.3. ADAT 1 In Interface for a device sending an ADAT signal to the Digiface.
Note that in record or monitor modes, set emphasis bits will disappear. Recordings originally done with emphasis should always be played back with the emphasis bit set! This can be done by selecting the Emphasis switch in the Settings dialog (field SPDIF Out). This setting is updated immediately, even during playback. Note: Recordings with (pre-) emphasis show a treble boost (50/15 µs), which has to be compensated at playback.
27. Word Clock 27.1 Technical Description and Usage In the analog domain one can connect any device to another device, a 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.
The word clock input of the Hammerfall DSP is a high-impedance type ensuring maximum flexibility, and is therefore not terminated. If normal termination is necessary (e.g. because Hammerfall DSP is the last device in the chain), simply connect a T-adapter to its BNC input jack, connect the cable supplying the word clock signal to one arm of the T-adapter and terminate the other with a 75 Ohm resistor (as a short BNC plug).
28. TotalMix: Routing and Monitoring 28.1 Overview The Digiface includes a powerful digital real-time mixer, the Hammerfall DSP mixer, based on RME’s unique, sample-rate independent TotalMix technology. It allows for practically unlimited mixing and routing operations, with all inputs and playback channels simultaneously, to any hardware outputs. Here are some typical applications for TotalMix: • Setting up delay-free submixes (headphone mixes).
User's Guide HDSP System Digiface © RME
28.2 The User Interface The visual design of the TotalMix mixer is a result of its capability to route hardware inputs and software playback channels to any hardware output. The Digiface provides 26 input channels, 26 software playback channels, and 28 hardware output channels: 52 channels don't fit on the screen side by side, neither does such an arrangement provide a useful overview. The input channel should be placed above the corresponding output channel.
28.3 Elements of a Channel A single channel consists of various elements: Input channels and playback channels each have a mute and solo button. Below there is the panpot, realized as indicator bar (L/R) in order to save space. In the field below, the present level is displayed in RMS or Peak, being updated about every half a second. Overs (overload) are indicated here by an additional red dot. Next is the fader with a level meter.
You see, it is very easy to set up a specific submix for whatever output: select output channel, set up fader and pans of inputs and playbacks – ready! For advanced users sometimes it makes sense to work without Submix View. Example: you want to see and set up some channels of different submixes simultaneously, without the need to change between them all the time. Switch off the Submix View by a click on the green button.
You will certainly have noticed that the signal at the outputs 7/8 did not change while you were routing channel 4 to other outputs and setting different gain values for those. With all analog and most digital mixing desks, the fader setting would affect the level for every routed bus - not so for TotalMix. TotalMix allows for setting all fader values individually. Therefore the faders and the panpots jump to the appropriate setting as soon as another routing is chosen.
28.7 The Quick Access Panel This section includes additional options, further improving the handling of TotalMix. The Master buttons for Mute and Solo have already been described, they allow for group-based working with these functions. In the View section the single mixer rows can be made visible or invisible. If the inputs are not needed for a pristine playback mix, the whole upper row falls out of the picture after a click on the Input button.
Mouse: The original factory presets can be reloaded by holding down the Ctrlkey and clicking on any preset button. Alternatively the files described above can be renamed, moved to a different directory, or being deleted. Keyboard: Using Ctrl and any number between 1 and 8 (not on the numeric keypad!) will load the corresponding factory default preset. The key Alt will load the user presets instead. When loading a preset file, for example 'Main Monitor AN 1_2 plus headphone mix 3_4.
28.9 The Monitor Panel The Monitor panel provides several options usually found on analog mixing desks. It offers quick access to monitoring functions which are needed all the time in typical studio work. Monitor Main Use the drop down menu to select the hardware outputs where your main monitors are connected to. Dim A click on this button will lower the volume of your main monitor output (see above) by an amount set up in the Preferences dialog (see below).
Main Monitor Dim: Amount of attenuation of the Main Monitor output in dB. Activated by the Dim button in the Monitor panel. Stereo Pan Law The Pan Law can be set to -6 dB, -4.5 dB, -3 dB and 0 dB. The value chosen defines the level attenuation in pan center position. This setting is useful because the ASIO host often supports different pan laws too. Selecting the same value here and in the ASIO host, ASIO Direct Monitoring works perfectly, as both ASIO host and TotalMix use the same pan law.
28.12 Hotkeys In many situations TotalMix can be controlled quickly and comfortably by the keyboard, making the mixer setup considerably easier and faster. The Shift-key for the fine mode for faders and panpots has already been mentioned. The Ctrl-key can do far more than changing the routing pairwise: • Clicking anywhere into the fader area with the Ctrl-key pressed, sets the fader to 0 dB. • Clicking anywhere into the pan area with the Ctrl-key pressed, sets the panorama to meaning Center.
28.13 Menu Options Always on Top: When active (checked) the TotalMix window will always be on top of the Windows desktop. Note: This function may result in problems with windows containing help text, as the TotalMix window will even be on top of those windows, so the help text isn't readable. Deactivate Screensaver: When active (checked) any activated Windows screensaver will be disabled temporarily. Ignore Position: When active, the windows size and position stored in a file or preset will not be used.
28.14 Level Meter The Digiface calculates all the display values Peak, Over and RMS in hardware, in order to be capable of using them independent of the software in use, and to significantly reduce the CPU load. Tip: This feature, the Hardware Level Meter, is used by DIGICheck (Windows only, see chapter 16) to display Peak/RMS level meters off all channels, nearly without any CPU load. The level meters integrated in TotalMix - considering their size - cannot be compared with DIGICheck.
29. TotalMix: The Matrix 29.1 Overview The mixer window of TotalMix looks and operates similar to mixing desks, as it is based on a conventional stereo design. The matrix display presents a different method of assigning and routing channels, based on a single channel or monaural design. The matrix view of the HDSP looks and works like a conventional patchbay, adding functionality way beyond comparable hardware and software soutions.
29.4 Advantages of the Matrix The Matrix not always replaces the mixer view, but it significantly enhances the routing capabilities and - more important - is a brilliant way to get a fast overview of all active routings. It shows you in a glance what's going on. And since the Matrix operates monaural, it is very easy to set up specific routings with specific gains.
30.2 Selection and Group-based Operation Click on the white name label of channel 1 and 2 in TotalMix. Be sure to have channel 3's fader set to a different position and click on its label too. All three labels have changed to the colour orange, which means they are selected. Now moving any of these faders will make the other faders move too. This is called 'building a group of faders', or ganging faders, maintaining their relative position.
30.5 Recording a Subgroup (Loopback) TotalMix supports a routing of the subgroup outputs (=hardware outputs, bottom row) to the recording software. Instead of the signal at the hardware input, the signal at the hardware output is sent to the record software. This way, complete submixes can be recorded without an external loopback cable. Also the playback of a software can be recorded by another software. To activate this function, click on the white label in the third row while holding down the Ctrlkey.
Recording a Software's playback In real world application, recording a software's output with another software will show the following problem: The record software tries to open the same playback channel as the playback software (already active), or the playback one has already opened the input channel which should be used by the record software. This problem can easily be solved.
Unfortunately, very often it is not possible within the record software to assign a different input channel to an existing track 'on the fly'. The loopback mode solves this problem elegantly. The routing scheme stays the same, with the input channel 1 sent to any output via TotalMix, to the Compressor, from the Compressor back to any input. Now this input signal is routed directly to output 1, and output 1 is then switched into loopback mode via Ctrl-mouse. As explained in chapter 30.
When Full LC Display Support is turned off, only a brief information about the first fader of the block (channel and row) is sent. This brief information is also available on the LED display of the Behringer BCF2000. Tip for Mac OS X users: LC Xview (www.opuslocus.com) provides an on-screen display emulating the hardware displays of a Logic/Mackie Control, for use with controllers that can emulate a Logic/Mackie Control but do not have a display. Examples include the Behringer BCF2000 and Edirol PCR-series.
31.5 Simple MIDI Control The stereo output faders (lowest row) which are set up as Monitor Main outputs in the Monitor panel can also be controlled by the standard Control Change Volume via MIDI channel 1. With this, the main volume of the Digiface is controlable from nearly any MIDI equipped hardware device. Even if you don't want to control all faders and pans, some buttons are highly desired to be available in 'hardware'.
User's Guide Digiface Technical Reference 70 User's Guide HDSP System Digiface © RME
32. Tech Info Not all information to and around our products fit in a manual. Therefore RME offers a lot more and detailed information in the Tech Infos. The very latest Tech Infos can be found on our website, section News & Infos, or the directory \rmeaudio.web\techinfo on the RME Driver CD. These are some of the currently available Tech Infos: Synchronization II (DIGI96 series) Digital audio synchronization - technical background and pitfalls. Installation problems - Problem descriptions and solutions.
33. Technical Specifications 33.1 Analog Stereo Monitor Output • Maximum output level at 0 dBFS: +8 dBu • Dynamic range: 108 dB (RMS unweighted, unmuted), 112 dBA • THD+N: -100 dB / 0.001 % • Channel separation: > 110 dB • Frequency response DA, -0.1 dB: 20 Hz - 20.8 kHz (sf 44,1 kHz) • Frequency response DA, -0.5 dB: 10 Hz - 44 kHz (sf 96 kHz) • Output impedance: 75 Ohm 33.2 Digital • • • • • • • Low Jitter Design: < 3 ns external clock, < 1 ns internal clock Internal sample rates: 32 / 44.1 / 48 / 88.
33.4 Digital Outputs SPDIF - AES/EBU • 1 x RCA, transformer-balanced, galvanically isolated, according to AES3-1992 • Output level Professional 2.3 Vpp, Consumer 1.0 Vpp • Format Professional according to AES3-1992 Amendment 4 • Format Consumer (SPDIF) according to IEC 60958 • Single Wire mode, sample rate 28 kHz up to 103 kHz ADAT • 3 x TOSLINK • Standard: 24 channels 24 bit, up to 48 kHz • Double Speed (S/MUX): 12 channels 24 bit 96 kHz Word Clock • BNC, max.
34. Technical Background 34.1 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.
34.2 Latency and Monitoring The term Zero Latency Monitoring has been introduced by RME in 1998 for the DIGI96 series of audio cards. It stands for 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.
Note: Cubase and Nuendo display the latency values signalled from the driver separately for record and playback. These values equal nearly exactly the buffer size (for example 3 ms at 128 samples) on RME's digital interfaces. Core Audios Safety Offset Under OS X, every audio interface has to use a so called satety offset, otherwise Core Audio won't operate click-free. The Digiface uses a safety offset of 32 samples.
34.4 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.
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