User’s Guide DMC-842 The Digital Microphone Interface ™ SyncAlign ™ MultiMode I64 Option Slot ™ SteadyClock ™ ™ SyncCheck 8-Channel Digital Microphone Interface with Line Outputs 8-Channel AES to Analog / ADAT Interface AES/EBU Format and Sample Rate Conversion Optional 64-Channel MADI Interface 24 Bit / 192 kHz Digital Audio MIDI Remote Control AES-3 AES-10 AES42 24 Bit Interface
Important Safety Instructions ..................................4 General 1 2 3 4 Introduction ...............................................................6 Package Contents .....................................................6 Brief Description and Characteristics.....................6 First Usage – Quick Start 4.1 Controls - Connectors - Displays ............................7 4.2 Quick Start ..............................................................9 5 Accessories ...............................
12 Remote Control 12.1 MIDI ..................................................................... 25 12.2 MIDI over MADI ................................................... 25 12.3 Remote Control Software .................................... 26 12.4 RS232 .................................................................. 28 Inputs and Outputs 13 14 15 16 17 Digital Inputs 13.1 XLR ...................................................................... 30 13.2 D-Sub – AES/EBU Sync ......................
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.
User’s Guide DMC-842 General User’s Guide DMC-842 © RME 5
1. Introduction The DMC-842 is both an AES/EBU interface as well as a controller for digital microphones. The unique device allows for connection and control of up to 8 digital microphones, and converting their signals to ADAT, AES/EBU, analog and (optional) MADI. Eight switchable hi-end sample rate converters offer a flexible clocking and further usage options. When developing the DMC-842, RME worked closely with the microphone manufacturers to secure maximum compatibility and best functionality.
4. First Usage – Quick Start 4.1 Controls - Connectors - Displays The front of the DMC-842 features eight LED level meter, eight numerical LED displays, eight Select keys, a rotary encoder, further keys for more specific configuration options, and 69 LEDs providing a detailed status display. Each channel has a dedicated configuration area on the front plate. The display GAIN shows the currently set amount of amplification.
The rear panel of the DMC-842 has eight AES42 inputs, eight analog outputs, mains power, MIDI I/O, word clock I/O, the I64 Option Slot, and all digital inputs and outputs (AES/ADAT). DIGITAL MICROPHONE – AES/EBU INPUTS (XLR): Eight balanced AES42 inputs with switchable digital phantom power (DPP). These inputs are compatible to AES3 and AES/EBU. ANALOG LINE BALANCED OUTPUTS (XLR): Eight balanced line outputs with up to +27 dBu level.
4.2 Quick Start After connection of all cables and power-on of the device, the configuration of the DMC-842 begins in the CLOCK section. Choose a clock source and a sample rate. The next step is the configuration of the input channels. When using digital microphones DPP (digital Phantom power) must be activated. In Mode 1 the SRCs have to be activated as well as soon as more than one microphone is connected. The next step is the GAIN setting.
I64 MADI Card MADI module featuring thru-input, Delay Compensation, Auto ID, MIDI over MADI, remote via MADI BOB32 BOB-32, Universal breakout box, 19" 1 Unit height. The professional digital AES/EBU breakout solution 6. Warranty Each individual DMC-842 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.
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.
User’s Guide DMC-842 © RME
User’s Guide DMC-842 Usage and Operation User’s Guide DMC-842 © RME 13
8. Front Panel Controls 8.1 Select Key and Rotary Encoder (SET) The rotary encoder SET is a highly intuitive multifunctional device. It is used to set the gain, to select the desired function, to deactivate the function of one or all channels, to select various options in the Setup menu and to perform the setting of the parameters. To activate a function, press the SET knob repeatedly until the corresponding LEDs are flashing.
8.2 Clock Section The source and frequency of the unit's clock is configured in the CLOCK SECTION. The button CLOCK lets you step through the options external clock (Word, AES, Option = MADI) and internal clock. The button SAMPLE RATE sets the sample rate for both external and internal clock. WCK, AES, OPTN (Slave Mode) Defines the corresponding input as clock reference. A missing or invalid clock source signal is indicated by flashing of the corresponding LED.
8.4 Remote REMOTE defines the source of MIDI remote control commands. Choices are the MIDI DIN jack, the D-sub AES1 and the MADI input of the I64 MADI Card (Option Slot). A firmware update added a fourth option, RS232, signaled by the LEDs OPTN and MIDI flashing alternately. Nevertheless RS232 is currently not functional. Note: Via MIDI remote control, all front panel controls can be locked (Lock Keys). An exception is the REMOTE key. In Off-state Lock Keys is deactivated.
9.4 Mode 2 In Mode 1 the digital microphone is clock master, operating from the internal and fixed frequency. When connecting more than one microphone, the usage of sample rate converters for clock-decoupling is unavoidable. In the newer Mode 2 the digital microphone is clock slave. The DMC-842 determines the frequency and generates a digital control signal for each microphone. A sample rate conversion is not required in this case.
9.7 SRC The DMC-842 includes eight individually switchable sample rate converters (SRC). The technical specifications indicate an exceptional conversion quality, formerly known only from synchronous SRC devices. The conversion in full 24 bit resolution operates practically without loss of signal quality, so no audible artifacts or noise are added. The SRC of the DMC-842 offers a maximum conversion rate of 1:7 or 7:1, respectively.
10. The Setup Menu 10.1 General Some options and settings are accessed and changed very seldom. These have been collected in the Setup menu. The Setup menu is entered by pushing SETUP, situated below the encoder. SEt is displayed on the left part of the Gain displays. Turning the encoder scrolls through all the options, displayed as abbreviation in the right part of the Gain displays. The Select key 8 allows to toggle the current setting, for example changing between On and Off.
10.4 Auto ID (Au) Default: Off Available settings: On, Off This option relates to the use of the I64 MADI Card. Multiple DMC-842 (and ADI642/Micstasy/ADI-8 QS, see chapter 14.3/14.4) connected serially can assign consecutive IDs to themselves. For this to happen, Auto ID is set to On at the first device of the chain. All other devices automatically turn into slaves. An Auto ID slave has the middle dot lit in the GAIN display of channel 8. 10.
10.6 Follow Clock (FC) Default: Off Available settings: On, Off The signal at the word clock or AES input can be Single, Double or Quad Speed, the DMC-842 can use it in any case, independent of its current clock range. When activating the option Follow Clock the DMC-842 follows the input clock 1:1. At 96 kHz the DS LED will light up automatically, at 192 kHz the QS LED.
10.10 Analog Output (Ao) Default: 42 Available settings: 42, oP This option relates to the use of the I64 MADI Card. In default state (42 = Mic) the XLR input signal is available at the analog outputs. Selecting oP (Option) an eight-channel group of the MADI input signal is sent to the analog outputs. With this the MADI connection can also be used as return path. Sending audio via MADI to the DMC-842, the audio becomes available at the DMC-842’s analog outputs.
10.14 Special (SPECIAL) Gives access to 5 special functions which are steered by the SELECT keys 1 to 5. The current state is signaled by the PAR LED. Here the function is directly switched off/on by the according SELECT key, not via key 8. SELECT 1: AES Sync for AES input 1 as sync source instead of the AES sync input at the Dsub connector. Default: Off. SELECT 2: Force sample rate for Mode2 microphones. This function can be switched off for microphones that work according to an old AES42 standard.
11.2 Low Cut (Lo-Cut) Default: Off Available settings: Off, 40, 80, 160 (display 0, 1, 2, 3) This option activates a high-pass (bass removal) within the microphone. This filter can remove rumble, subsonic-noise and other low frequency noises. The cut-off frequency can be set to 40 Hz, 80 Hz and 160 Hz. 11.
12. Remote Control 12.1 MIDI The DMC-842 can be completely remote controlled via MIDI. It reacts on special SysEx commands. Furthermore, upon request it will report the complete device status, including all controls and LEDs on the front plate. Each DMC-842 can be programmed with its own ID, providing a separated remote control of multiple devices via a single MIDI channel. A description of the MIDI implementation is found in chapter 21.
The block diagram shows the signal flow in a HDSP MADI-based remote control system. MIDI commands from a software on PC or Mac travel from the MADI Out of the HDSP MADI to the MADI In as well as to the MIDI Out and MADI Out of the DMC-842. Additional to the remote commands further MIDI data can be transmitted, available then at the DIN MIDI output jack of the DMC842. However, MIDI signals at the DIN input jack can not travel back to the computer. With input setting MIDI the other direction is active.
The button Send Data allows an offline configuration of the DMC-842 by a single one-time transmission of all settings. The button Receive Data allows a one-time request of all settings of all DMC-842. Via File / Save complete setups with up to 8 DMC-842 can be saved and recalled anytime. Via MIDI remote control, all front panel controls of the DMC-842 can be locked (Lock Keys). An exception is the REMOTE key. In the Off-state the function Lock Keys is deactivated.
12.4 RS232 The DMC-842 is already equipped with a serial interface port. Please note that this port is without functionality at this time and reserved for future upgrades.
User’s Guide DMC-842 Inputs and Outputs User’s Guide DMC-842 © RME 29
13. Digital Inputs 13.1 XLR At the rear side of the DMC-842 there are eight XLR sockets for the AES42 inputs. All inputs are transformer-balanced, ground-free and compatible to AES3. Channel status and copy protection are being ignored. Thanks to a highly sensitive input stage, SPDIF signals can also be processed by using a simple cable adapter phono/XLR. To achieve this, pins 2 and 3 of a male XLR plug are connected individually to the two pins of a phono plug.
14. Digital Outputs 14.1 AES/EBU The four AES/EBU outputs are provided on the rear of the DMC-842 via a 25 pin D-sub connector with Tascam pinout (also used by Digidesign). A digital breakout cable will provide 4 male (and 4 female) XLR connectors. Every 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.
14.2 ADAT Optical The DMC-842 provides two digital outputs in ADAT optical format. In normal operation these ports carry the converted analog input signal. When using the I64 MADI Card and activating the option oP in the Setup menu do, the MADI input data is present at the output instead, see chapter 11.11. In Single Speed mode both outputs carry the same audio data. With this it is possible to distribute the output signal to two devices (2 x ADAT splitter).
14.3 I64 MADI Card The I64 MADI Card provides the DMC-842 with a 64-channel MADI input and output. Coaxial and optical output operate simultaneously and deliver the same data. The ID determines which MADI channels the DMC-842 will use (see chapter 10.2, ID). The MADI outputs operate in parallel to the AES/EBU and ADAT outputs, provide the same audio data, and are configured with the same front panel controls. The I64 MADI Card features an optical as well as a coaxial MADI input.
Delay Compensation has to be manually activated in each unit! 14.4 Differences serial MADI with I64 MADI Card and ADI-642 I64 MADI Card: Activate Auto ID in the first unit (ID of the master can be changed). All following units become Slave, get a consecutive ID, and with this the according channel routing. If desired, Delay Compensation has to be manually activated in each unit. ADI-642: Activate ADC (Auto Delay Compensation) in the first unit (ID of the master is always 1).
15. Analog Outputs The DMC-842 has 8 balanced XLR outputs on the back panel. The electronic output stage does not operate servo balanced! When connecting unbalanced equipment, make sure pin 3 of the XLR output is not connected. A connection to ground can cause a higher THD value (higher distortion)! The button ANALOG OUT is used to define the analog reference level at the analog outputs.
16. Word Clock 16.1 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 DMC-842's 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 DMC-842 automatically adapts to it.
16.2 Operation and Technical Background 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.
16.3 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.
User’s Guide DMC-842 Technical Reference User’s Guide DMC-842 © RME 39
18. Technical Specifications 18.1 Analog DA-conversion • Resolution: 24 Bit • Signal to Noise ratio (SNR) @ +24 dBu, 44.1 kHz: 116,0 dB RMS unweighted, 119 dBA • Signal to Noise ratio (SNR) @ +19 dBu: 116 dB RMS unweighted, 119 dBA • Signal to Noise ratio (SNR) @ +13 dBu: 116 dB RMS unweighted, 119 dBA • Frequency response @ 44.1 kHz, -0.5 dB: 5 Hz – 22 kHz • Frequency response @ 96 kHz, -0.5 dB: 5 Hz – 34 kHz • Frequency response @ 192 kHz, -1 dB: 5 Hz - 50 kHz • THD: < -104 dB, < 0.
18.3 Digital Outputs AES/EBU • 4 x, transformer-balanced, galvanically isolated, according to AES3-1992 • Output voltage 4.5 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.
18.6 General • • • • • • • • Power supply: Internal switching PSU, 100 - 240 V AC, 60 Watts Typical power consumption: 24 Watts Maximum power consumption: < 40 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 18.
Yamaha: Signal D-Sub Signal D-Sub In 1/2+ 1 In 1/214 In 3/4+ 2 In 3/415 In 5/6+ 3 In 5/616 In 7/8+ 4 In 7/817 Out 1/2+ 5 Out 1/218 Out 3/4+ 6 Out 3/419 Out 5/6+ 7 Out 5/620 Out 7/8+ 8 Out 7/821 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.
19. Technical Background 19.1 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.
19.2 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.
19.3 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.
19.4 DS - Double Speed When activating the Double Speed mode the DMC-842 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.
19.6 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.
19.7 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.
19.8 SteadyClock The SteadyClock technology of the DMC-842 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 synchronization. SteadyClock requires only one quartz, using a frequency not equalling digital audio.
20.
21. MIDI Implementation DMC-842 21.1 Basic SysEx Format Value F0h 00h 20h 0Dh 42h 00h..77h, 7Fh mm nn oo F7h Name SysEx header MIDITEMP manufacturer ID Model ID (DMC-842) Bank number / device ID (7Fh = broadcast, all IDs) Message type Parameter number (see table 1) Databyte EOX Bank Number / Device ID The lower nibble refers to the device ID (0..7), the higher nibble refers to the bank number (0..7), e. g. 25h means bank 2, device 5. 7Fh addresses all banks and all devices. 21.
Request Microphone Data Format: F0 00 20 0D 42 (bank no. / dev ID) (40..47) F7 This string triggers a complete dump of AES42 data of the microphone at input 1 to 8. Microphone Data Response After being triggered by receiving a request microphone data command, device sends a string of one channel’s complete AES42 microphone data. Message type is set to 32h. Set Microphone Value Sets any number of parameters. AES42 commands are transmitted in groups of 4 Bytes (nn1, nn2, oo1, oo2).
21.3 Table Set Val. No. No. Name 00h 01h 02h 03h 04h 05h 06h 07h 08h 09h 0Ah 0Bh 0Ch 0Dh 0Eh 0Fh 10h 11h 12h 13h 14h 15h 16h 17h 18h 19h 1Ah 1Bh 1Ch 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 Ch. 1 Gain Ch. 1 settings Ch. 2 Gain Ch. 2 settings Ch. 3 Gain Ch. 3 settings Ch. 4 Gain Ch. 4 settings Ch. 5 Gain Ch. 5 settings Ch. 6 Gain Ch. 6 settings Ch. 7 Gain Ch. 7 settings Ch. 8 Gain Ch.
10h Setup 1 (d.c. for clock sel > 0) 11h Setup 2 MSB / 7 6 5 4 3 MSB / 1 LSB / 0 MSB / 1 LSB / 0 2 1 MSB / 1 LSB / 0 LSB / 0 Int. Freq.: 0 = 44.
14h 15h 16h Channel Lock / Sync 3 (Request only) 5 (Request only) (Request only) (Request only) (Request only) (Request only) 4 3 2 1 LSB / 0 Channel Lock / Sync 4 0 (reserved) Input 6 RX AES42: 0 = Mode 1, 1 = Mode 2 Input 5 RX AES42: 0 = Mode 1, 1 = Mode 2 Input 6 Sync: 0 = no sync, 1 = sync Input 6 Lock: 0 = unlock, 1 = lock Input 5 Sync: 0 = no sync, 1 = sync Input 5 Lock: 0 = unlock, 1 = lock (Request only) 5 (Request only) (Request only) (Request only) (Request only) (Request only) 4 3 2
