User’s Guide OctaMic XTC The Professional’s Multi-format Solution ™ AutoSet ™ SteadyClock ™ QuickGain 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.
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 ...............................
Class Compliant Mode 16 17 18 General..................................................................... 38 System Requirements ............................................ 38 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 ....................................
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 OctaMic XTC General User’s Guide OctaMic XTC © RME 5
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.
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 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.
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 – Digital Routing.
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.
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 OctaMic XTC © RME
User’s Guide OctaMic XTC Usage and Operation User’s Guide OctaMic XTC © RME 13
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.
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.
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.
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.
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.
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.
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 is the 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.
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.
9. The Input Channel in Detail 9.1 Gain The OctaMic’s 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% reproducible. 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.
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.
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 unit causes a delay of several samples. This problem is solved by the function Delay Compensation.
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.
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 24.
User’s Guide OctaMic XTC Inputs and Outputs User’s Guide OctaMic XTC © RME 27
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.
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).
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.
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 D-sub In 1/2+ 24 In 1/212 In 3/4+ 10 In 3/423 In 5/6+ 21 In 5/69 In 7/8+ 7 In 7/820 13.2 ADAT Optical The OctaMic XTC provides two digital outputs in ADAT optical format.
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.
User’s Guide OctaMic XTC © RME 33
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.
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.
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.
User’s Guide OctaMic XTC Class Compliant Mode User’s Guide OctaMic XTC © RME 37
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).
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.
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.
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.
User’s Guide OctaMic XTC © RME
User’s Guide OctaMic XTC Technical Reference User’s Guide OctaMic XTC © RME 43
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.
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.
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.
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.
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 D-Sub Signal D-Sub In 1/2+ 24 In 1/212 In 3/4+ 10 In 3/423 In 5/6+ 21 In 5/69 In 7/8+ 7 In 7/820 Out 1/2+ 18 Out 1/26 Out 3/4+ 4 Out 3/417 Out 5/6+ 15 Out 5/63 Out 7/8+ 1 Out 7/814 GND is connected to pins 2, 5, 8, 11, 16, 19, 22, 25. Pin 13 is not connected.
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.
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.
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.
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.
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.
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.
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.
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.
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.
23.
24. MIDI Implementation OctaMic XTC 24.1 Basic SysEx Format Value F0h 00h 20h 0Dh 69h 00h..7Eh, 7Fh mm nn F7h Name SysEx header MIDITEMP manufacturer ID Model ID (OctaMic XTC) MIDI device ID Command ID Data (parameter index, parameter LSB, parameter MSB, set-flags, ...) EOX 24.
24.3 Table Commands ID 0x10 0x11 0x12 0x20 0x30 Command request all parameters (incl. level data) request level data request changed parameters (in case of no changes: empty block) set parameter (multiple parameters allowed) send parameters (multiple parameters possible) Send Rec x x x x x Parameters Index 0 1 2 3 4 5 6 7 Send x x x x x x x x Rec x x x x x x x x Flag s.d. s.d. s.d. s.d. s.d. s.d. s.d. s.d.
MIDI Source Select Bit 0-2: Source USB1 Output (see Value Table 2) Bit 3-6: Source USB2 Output (see Value Table 2) Bit 0-2: Source DIN Output (see Value Table 2) Bit 3-6: Source MIDI over MADI (see Value Table 2) x 24 LSB MSB Group Enable Bit 0-3: Group 1..4 enable (ON) Bit 0-3: Group 1..4 AutoSet (AS) x 25 LSB MSB Save/Load Preset (Receive only) Load Preset 1..6, 0 for no operation Save Preset 1..
Phones Settings Source Bit 0..6 Bit 0: Bit 7 Source (see Value Table 1) Bit 1: Mute Bit 2-3: Phase Invert (0: off, 1: both, 2: left, 3: right) Bit 4: Level (0: Low, 1: High) LSB MSB LSB MSB Value 0x01 0x02 0x04 0x08 Level Meter (Send only) Channel 1 Channel 2 126: OVR 125..95: 0dB..-6dB (p[dB] = (Value – 125) * 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. s.d. not assigned see details Value Table 1 – Phones Sources 0.
