User’s Guide ADI-2 DAC FS Sonus Verus 32 Bit / 768 kHz Hi-Res Audio SteadyClock FS SyncCheck 2 Channel Digital / Analog Converter SPDIF (AES/ADAT) Interface 32 Bit / 768 kHz Digital Audio USB 2.
General 1 2 3 4 5 Introduction ...............................................................5 Package Contents .....................................................5 System Requirements ..............................................5 Brief Description and Characteristics.....................6 First Usage - Quick Start 5.1 Connectors and Controls ........................................7 5.2 Quick Start ..............................................................7 5.3 Operation at the unit..............
Inputs and Outputs 18 19 Digital Inputs ........................................................... 36 Analog Outputs 19.1 General ................................................................ 36 19.2 Line Out RCA....................................................... 36 19.3 Line Out XLR ....................................................... 37 19.4 Phones Out .......................................................... 37 19.5 IEM Out................................................................
Technical Reference 30 Technical Specifications 30.1 Digital Inputs ........................................................52 30.2 Analog Outputs ....................................................52 30.3 Digital ...................................................................53 30.4 General ................................................................53 30.5 Connector Pinouts................................................53 31 Technical Background 31.1 Lock and SyncCheck .........................
1. Introduction RME’s ADI-2 DAC is a true milestone in many ways. Looking at the multitude of DA converters, USB DACs and dedicated headphone amps available, RME developers felt they all lacked obvious features that are unavoidable to enjoy operation as well as when listening to music.
4. Brief Description and Characteristics The ADI-2 DAC is a 2-channel digital to analog converter in a half-rack (9.5") enclosure of 1 U height. Latest 32 bit / 768 kHz converters offer up to 120 dBA signal to noise ratio. This value is not only printed in the brochure – it is what the unit achieves in real-world operation. Reference class tech specs throughout are combined with an unprecedented feature set.
5. First Usage – Quick Start 5.1 Connectors and Controls The front of the ADI-2 DAC has 3 hi-precision rotary encoders with push function, 4 buttons, a standby power button, a high resolution IPS display, and two TRS headphone outputs. The output channels Phones and IEM feed two phones outputs via two independent driver circuits, optimized for both high and low impedance headphones. Their unbalanced output signal is of highest quality.
5.3. Operation at the Unit Useful information for a smooth start: Turning the big VOLUME knob brings up the Volume screen of the currently active output. The status bar at the bottom of the display shows the current volume settings' dB value. The header shows the currently selected output, the hardware reference level and Auto Ref Level mode if activated (Ref Lev, see chapter 12.1).
5.4. Overview Menu Structure 1 means upper small encoder (B), 2 lower small encoder (T). Rotate moves horizontally, press vertically (1 up, 2 down) through the menu structure. User’s Guide ADI-2 DAC v2.
5.5 Playback In the audio application being used, the ADI-2 DAC must be selected as output device. It can often be found in the Options, Preferences or Settings menus, as Playback Device, Audio Devices, Audio etc. After selecting a device, audio data is sent to the ADI-2 DAC and available at its analog outputs. Increasing the number and/or size of audio buffers and/or buffer size may prevent the audio signal from breaking up or having drop outs. 5.
7. Firmware Update The ADI-2 DAC might receive improved features or bug fixes by a firmware update. This update will be available from the RME website, section Downloads, USB. Download the tool that matches your operating system (Mac or Windows), then unpack the zipped archive. The Flash Update Tool updates the firmware of the ADI-2 DAC to the latest version. Under Windows it requires an already installed MADIface series driver, which is found on the same download page. Start the Flash Update Tool.
8. Features Explained 8.1 Extreme Power Headphone Outputs During the development of the ADI-2 Pro an extensive research on today’s headphone amp technology as well as headphones has been carried out. Many (many!) headphones later a maximum output level of +22 dBu (10 Volt) was set as development goal, as it will drive even insensitive headphones sufficiently, while a maximum output current of around 260 mA per channel will result in lots of power for lower impedance phones (1.5 Watts @ 32 Ohm).
8.2 IEM Phones Output In Low Power mode, the Extreme Power design of the ADI-2 DAC turns it into one of the world's lowest noise headphone outputs. However, a few IEMs are so incredibly sensitive (means loud) that, despite all the technical super specs, a faint noise could become audible (current example: Campfire Andromeda, at least 20 dB louder as modern, already as loud categorized headphones).
8.4 Bass / Treble The simpler form of EQ has been the Bass and Treble controls as they are found on any ‘standard’ HiFi stereo amplifier. They easily and quickly allow to modify the sound to your personal liking (more or less Bass, more or less Treble, obviously). An even more useful application is to quickly change the amount of Bass / Treble in smaller quantities so that music compilations don’t have one song making the cones fall out while another one makes you think that really happened.
8.6 Crossfeed While headphones open the sound stage and make everything easier to hear and to locate by spreading the narrow sound field of stereo speakers to the left/right extreme, some people would like to have a listening situation that is more comparable to a standard speaker setup. The ADI-2 DAC includes Crossfeed to address this wish. Crossfeed reduces the artificial surround ambience that some productions have to make them sound better on speakers, but which sounds unnatural on a headphone.
8.8. DSP Limitations There is never enough DSP power – no matter how much you add (frustrated developer). That is true even for the ADI-2 DAC. Although being equipped with a quite capable 2.17 Giga FLOPS DSP chip, plus using the FPGA to perform further calculations (RME’s virtual DSP for mixing/routing, level meters, filtering, Crossfeed), 768 kHz sample rate takes its toll. The calculation power available at 48 kHz is divided by 16 (!) then. Even at 384 kHz it is just 1/8 of that at 48 kHz.
User’s Guide ADI-2 DAC Operation, Controls and Display User’s Guide ADI-2 DAC v2.
9. RME Multi-Remote Control (MRC) The included infrared remote control, manufactured exclusively for RME, offers an almost complete remote control of the ADI-2 DAC in a clear way. It works immediately without further settings on the device, since the DAC code table is pre-set from factory. Pressing a button therefore causes the SEL LED to light up green. If the LED is orange, red or blue, another reserved code table is active that is not compatible with the ADI-2 DAC.
9.2 Other Remote Controls The ADI-2 DAC can also be remotely controlled using third-party remote controls and custom IR transmitters. The well-known manufacturer Logitech has added the ADI-2 DAC to its remote control database. Others can use the codes documented here: http://www.rme-audio.de/download/adi2dac_ir_commands.zip Available are the original keys of the MRC and all 32 Remap commands with direct access (without remapping). 10.
11. VOL The VOL key brings up an extended volume screen with balance control. Volume can then be adjusted by both Volume knob and encoder 1. Encoder 2 sets the Balance parameter. The volume and balance setting is also found in the menu I/O - Settings, at the end of the list. The status bar at the bottom of the display shows the volume setting's current dB value. A push on encoder 1 (B) mutes the current output. The text in the blue field shows Line Out - muted. A second push exits the mute state.
12.1 Subpage Settings Source The source of the analog output signal: Auto, SPDIF coax, Optical, USB, USB (Rec coax), USB (Rec opt.). Default: Auto. In Auto Mode any detected SPDIF Signal will have priority over USB playback. Record SPDIF optical and Record SPDIF Coaxial activate the full duplex operation with USB: The respective SPDIF signal is clock source and can be recorded via USB. The analog output signal is the current USB playback, in case the sample rate is identical to the SPDIF input.
Dual EQ OFF or ON. Default: OFF. When set to ON, the 5-band parametric equalizer can be set individually for left and right channel. Volume Mirrors the direct volume control via Volume knob or encoder 1. The output level can be set between -96 dB and +6 dB, mostly in steps of 0.5 dB. The encoders use a special accelerator algorithm. Fast turning increases the step size. At moderate turning speed the changes in dB cause the expected volume change. Only at slower turning the finest steps will be used.
12.3 Subpage Bass / Treble B/T Enable OFF, ON. Default: ON Bass Gain Current Bass amplification for the current channels as set by encoder 1 (B). Adjustable between -6 dB and +6 dB in steps of 0.5 dB. Bass Freq Corner frequency of the shelf bass filter. Adjustable from 20 Hz to 150 Hz in steps of 1 Hz. Default: 85 Hz. Bass Q The quality factor of the filter is adjustable from 0.5 to 1.5. Default 0.9. Treble Gain Current Treble amplification for the current channels as set by encoder 2 (T).
13. EQ The key EQ brings up a graphical EQ display (Bode plot) screen to set the EQ quickly and with full overview for the current output. The I/O - Settings submenu Parametric EQ mirrors the settings done in this screen. Turning encoder 2 or pushing VOLUME repeatedly scrolls through all 5 bands, as can be seen in the parameter line (B1 to B5). VOLUME steers the gain of the current band, the other parameters are not available for adjustment.
Notes The frequency graphics give a precise overview of the filter results. Overlapping filters influence each other. This can be used to achieve more than 12 dB gain, or to generate difficult frequency response optimizations. The ADI-2 DAC has an internal headroom of 24 dB. Extreme boosts with overlapping filters could cause an internal overload. Such an overload will be visible as it is displayed by the level meter below the EQ, as well as the channel’s level meter.
14. SETUP The key Setup gives access to two top level screens: Options and Load/Store all Settings. Options has the subpages Remap Keys / Diagnosis, Phones / DSD, Clock and Display. 14.1 Options 14.1.1 Remap Keys / Diagnosis Subpage Remap Keys /Diagnosis, has the following entries: Remap Keys OFF, ON, Remote. Default: Remote. Allows to assign 32 different functions/actions to the four function keys on the unit and on the remote, or the remote only.
14.1.2 Clock The subpage Clock has the following entries: Clock Source Shows the current clock source INT (internal), optical or SPDIF coaxial. The clock source is automatically determined and set by the unit, a selection is neither possible nor necessary. With USB the internal clock is used, with SPDIF the external one. Sample Rate The sample rate is also automatically determined and set by the unit.
14.1.4 Display The subpage Display has the following entries: Display Mode Available settings are: Default, Dark. The dark scheme inverts the white background and black numbers/text to black background and light-grey numbers/text in all menus. Meter Color Green, Cyan. Amber. Default: Green. Sets the meter screen colour in PCM and DSD mode. Hor.
15. Top Screens The ADI-2 DAC has four different top screens: an Analyzer showing the audio signal content of the analog outputs, a State Overview showing the digital states of SPDIF and USB, a Dark Volume screen with some additional information, and Dark Volume Details, showing all currently active DSP functions. Pushing the small encoder 1 or 2 cycles through them if any is currently active. To quickly call them up simply press any of the four function keys one or two times.
As opposed to most other solutions no FFT (Fast Fourier Transform) is used. RME's Spectral Analyzer performs a true band-pass filter calculation, as in professional hardware devices. The frequency distance between the filters is scaled matching human hearing. The highly optimized code allows to run a 30 band analyzer with 60 dB range, sharp filters and 0.5 dB steps accuracy per band, on the ADI-2 DAC DSP, even at 768 kHz sample rate.
The Bit column shows the amount of bits found in the SPDIF audio signal. Note that a 24 bit signal that is shown as 16 bit is indeed 16 bit, but a signal shown as 24 bit might contain only 16 bit real audio plus 8 bits of noise… But SPDIF can also transport AC-3 and DTS encoded surround sound. This signal sounds like chopped noise at full volume. Therefore the ADI-2 DAC receiver circuit checks the Non-Audio flag within the Channel Status. If found the signal is already muted directly in the receiver.
DC detected (Phones) DC detection is crucial to prevent the sensitive phones drivers from being destroyed by inaudible currents flowing through them. As the ADI-2 DAC is fully DC coupled from DAC to phones output, a digital full scale signal with 0 Hz would produce up to 15V DC at the outputs, and destroy any attached phone immediately. In case the power output stage fails the same could happen. Therefore the phones outputs will switch off with 1.8V DC detected.
17. DSD 17.1 General DSD (Direct Stream Digital) is a stream with single bit resolution, but multiple times the sample rate of the CD. DSD64 equals 64 times 44.1 kHz = 2.8 MHz, DSD128 5.6 MHz, DSD256 11.2 MHz. Versions with multiples of 48 kHz also exist, up to 12.2 MHz. To transfer DSD data over SPDIF, AES or even USB, DSD over PCM (DoP) is the de-facto standard.
17.3 DSD Playback While most DACs, even ones seen as 'Hi-End', leave the user clueless during DSD operation, the ADI-2 DAC continues to show level as well as spectral content. To be able to show the analog I/Os audio signals on level meters and Analyzer the DSP performs an additional DSD to PCM conversion. Analyzer and level meter show DSD signals in blue colour for Green and Cyan, the current mode is therefore easy to recognize (Amber gets a bit lighter).
User's Guide ADI-2 DAC Inputs and Outputs User’s Guide ADI-2 DAC v2.
18. Digital Inputs Two SPDIF inputs are available, optical via TOSLINK and coaxial via RCA, but only one can be used at a time. The currently used SPDIF input can be chosen under I/O - Settings – Source. Set to Auto the input with a valid input signal will be chosen automatically. The optical input also understands ADAT format, up to 192 kHz, but only channels 1/2 of the 8channel signal are available. Using a simple cable adapter XLR to RCA, an AES/EBU signal can be received too.
19.3 Line Out XLR The ADI-2 DAC has two balanced analog outputs that can operate at levels up to +21.5 dBu (+19 dBu with Volume set to +2.5 dB). The short circuit protected, low impedance line outputs are available as XLR jacks on the back of the unit. ! The XLR line outputs do not operate servo balanced! When connecting unbalanced equipment, make sure pin 3 of the XLR output is not connected.
19.5 IEM Out This output via stereo mini-TRS is optimized for the use of high-quality IEMs, but generally works very well with portable headphones that do not require high power or voltage. The IEM output might be the world's lowest-noise headphone output at an output impedance of less than 0.1 Ohm, and without resorting to tricks such as a voltage divider with resistors at the output. Maximum output level is -0.5 dBu (-3 dBu with Volume set to +2.5 dB), equalling 0.73 Vrms.
User's Guide ADI-2 DAC Installation and Operation – Windows User’s Guide ADI-2 DAC v2.
20. Driver Installation Since FPGA firmware 17 the ADI-2 DAC is fully compatible to Windows 10 (1709 or newer). The unit is automatically recognized when connected to the computer. WDM and WASAPI, from 44.1 to 384 kHz, and DSD playback via DoP (needs to be set in the respective player software) up until DSD256 will work directly, without any installed driver. Installing the RME drivers adds ASIO (PCM, DSD DoP and DSD Native), and extends WDM up to 768 kHz.
21. Configuring the ADI-2 DAC 21.1 Settings Dialog Configuration of the ADI-2 DAC is usually done directly at the unit. For ASIO operation sample rate and buffer size (latency) can be set via a dedicated settings dialog. The panel 'Settings' can be opened by clicking on the fire symbol in the Task Bar's notification area Any changes made in the Settings dialog are applied immediately confirmation (e.g. by clicking on OK or exiting the dialog) is not required.
21.2 Clock Modes - Synchronization In the digital world, all devices must be either Master (clock source) or Slave (clock receiver). Whenever several devices are linked within a system, there must always be a single master clock. ! A digital system can only have one master! If the ADI-2 DAC’s clock mode is set to 'Internal', all other devices must be set to ‘Slave’. To cope with some situations which may arise in studio practice, defining a sync reference is essential.
22.3 Multi-interface Operation The current driver supports up to three RME devices of the MADIface series. All units have to be in sync, i.e. have to receive valid digital sync information. Under ASIO all devices are presented as one ASIO device with all available channels as I/Os. If one of the units is set to clock mode Master, all others have to be set to clock mode Slave, and have to be synced from the master by feeding ADAT, AES or SPDIF.
User’s Guide ADI-2 DAC v2.
User's Guide ADI-2 DAC Installation and Operation – Mac OS X User’s Guide ADI-2 DAC v2.
24. General The ADI-2 DAC is a UAC 2.0 Class Compliant device. Mac OS X has full UAC support built-in, there is no driver installation required. Connect computer and ADI-2 DAC with a USB cable. Mac OS X detects the new hardware as ADI-2 DAC (serial number). For firmware updates please see chapter 7. 24.1 Configuring the ADI-2 DAC Configuration of the ADI-2 DAC is mostly done directly at the unit. When set to Clock Source Internal, Mac OS X will set the current sample rate.
24.3 Multi-interface Operation OS X supports the usage of more than one audio device within an audio software. This is done via the Core Audio function Aggregate Devices, which allows to combine several devices into one. All units have to be in sync, i.e. have to receive valid sync information via a digital input signal, then all channels can be used at once.
User’s Guide ADI-2 DAC v2.
User's Guide ADI-2 DAC Installation and Operation – iOS User’s Guide ADI-2 DAC v2.
26. General The ADI-2 DAC operates in Class Compliant mode (UAC 2.0), a standard that is natively supported by operating systems like iOS, Mac OS X, Linux and Windows 10 (since 1709). No proprietary drivers are required, the device will be directly recognized. The ADI-2 DAC provides iOS devices with the professional I/O connections they lack.
User's Guide ADI-2 DAC Technical Reference User’s Guide ADI-2 DAC v2.
30. Technical Specifications 30.1 Digital Inputs General • Lock Range: 44 kHz – 200 kHz • Jitter suppression: > 50 dB (2.4 kHz) • Accepts Consumer and Professional format SPDIF coaxial • 1 x RCA, according to IEC 60958 • High-sensitivity input stage (< 0.3 Vpp) • AES/EBU compatible (AES3-1992) SPDIF optical • 1 x optical, according to IEC 60958 • ADAT compatible 30.
IEM As Phones, but: • Output level at 0 dBFS: -3 dBu, 0.55 V • Signal to Noise ratio (SNR) @ -3 dBu: 118 dB RMS unweighted, 121 dBA • Max power, 8 Ohm, 0.001% THD: 40 mW per channel 30.3 Digital • • • • • • • Clocks: Internal, SPDIF In Jitter suppression of external clocks: > 50 dB (2.
31. Technical Background 31.1 Lock and SyncCheck 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 base. 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.
31.2 Emphasis In the early times of digital audio, with AD and DA converters of only 14 bit resolution, a technique was used that is also known from radio transmission: pre- and de-emphasis. The audio signal is equalized to have treble boosted before the conversion. When played back an analog treble filter (the term high cut seems a bit strong) is required. Overall the audible noise and distortion caused by the AD and DA conversion was hoped to be reduced this way.
31.4 DA Impulse Responses Short delay Sharp Sharp Short Delay Slow Slow The screenshots above show the analog output signal of the DAC filters, stimulated by a digital single sample impulse at 44.1 kHz sample rate. While Slow has the most perfect response, it looses around 1.2 dB already at 15 kHz, see chapter 31.4. Both Short Delay are IIR filters, the other two are FIR type. FIR is phase linear over the whole frequency range.
SD LD (Short Delay Low Dispersion) In theory, a filter should have as little phase deviation as possible over the frequency range, have as short a settling time as possible, an acceptable decay time, and provide the maximum possible frequency range without deviation. The stopband attenuation should be high to prevent aliasing. A latency as low as possible would extend the application possibilities to more than just listening to music.
31.6 DA Frequency Response per Sample Rate Note: 44.1 kHz to 192 kHz measured with DA Filter Sharp. 31.7 Loudness 58 User’s Guide ADI-2 DAC v2.
31.8 Total Harmonic Distortion Measurements Outputs XLR and TS* Output Phones TRS* ** * Measured with active notch filter via ADC of ADI-2 Pro FS ** 18 dBu output level equal 1.2 W (per channel) User’s Guide ADI-2 DAC v2.
31.9 Extreme Power Charts 60 User’s Guide ADI-2 DAC v2.
31.10 Phones Distortion Comparison 31.11 Impedance based Level Meters (Phones) The horizontal level meters in various screens of outputs 1 to 4 show the digital level fed to the DAC. Above 32 Ohms the level meter's display matches the real analog output level (0 dBFS = +22 dBu). But at 32 Ohms the ADI-2 DAC delivers only +19 dBu, at 16 Ohms +15 dBu to the phones outputs, because a reasonable current limiting circuit prevents a too high output power at lower load impedances.
31.12 USB Audio An ADI-2 DAC can achieve a performance similar to a PCI or PCI Express based soundcard when used with an optimal PC. Low CPU load and click-free operation even at 64 samples buffer size are indeed possible on current computers. However, using older computers a simple stereo playback will begin to cause a CPU load of more than 30%. A computer blocked for a short time – no matter if ASIO or WDM – will lose one or more data packets.
31.13 Operation in the Hi-Fi Environment Do the advantages of the ADI-2 DAC's fully symmetrical design still exist when using unbalanced connections (RCA)? Yes. On the output side RME uses a specially developed servo-balanced DAC filter, which provides both paths of the balanced design with full noise and distortion ratios.
31.14 Digital Volume Control The ADI-2 DAC deliberately avoids an analog level adjustment by means of a potentiometer. Its digital version surpasses an analog one in practically every conceivable point. Typical disadvantages of setting with potentiometers: • Synchronicity errors lead to panoramic shifts and significant volume deviations left / right, in particular near the end points of the adjustment range.
The following measurement shows a digital full-scale sine of 1 kHz, 16 bits without dither, which is reduced in level by 40 dB. Also shown are a full-scale sine of 1 kHz with 24 bit, at 60 dB and 93.8 dB level attenuation, which is the lowest volume setting the ADI-2 DAC offers. A high-resolution FFT like HpW Works makes it possible to disassemble the signal into individual frequencies, and to identify unwanted components down to a level of -190 dBFS.
31.15 Bit Test A bit test is used to check the playback path for unwanted changes in the playback data. Playback software can cut bits, add dither, or change the level - without these changes becoming noticed easily. A poorly programmed driver can manipulate bits, and a playback hardware could be both badly designed and defective (hanging bits, swapped bits). Even such features as proper channel assignment, left/right synchronicity and polarity can be tested by a well-made bit test.
31.16 Block Diagram User’s Guide ADI-2 DAC v2.
User’s Guide ADI-2 DAC v2.
User's Guide ADI-2 DAC Miscellaneous User’s Guide ADI-2 DAC v2.
32. Accessories There are several items available for the ADI-2 DAC: Part Number Description NT-RME-2 (lockable) Power supply for ADI-2 DAC. Robust and light-weight switching power supply, 100 V-240 V AC, 12 V 2 A DC. Lockable DC connector. USB Cable, 2m RME USB 2 cable, length 78” (2m) MRC RME Multi Remote Control, infrared remote control Optical cables for SPDIF and ADAT operation: OK0100PRO OK0200PRO OK0300PRO Optical cable, TOSLINK, 1 m (3.3 ft) Optical cable, TOSLINK, 2 m (6.
34. Appendix RME news, driver updates and further product information are available on RME’s website: http://www.rme-audio.com Worldwide distribution: Audio AG, Am Pfanderling 60, D-85778 Haimhausen, Tel.: (49) 08133 / 918170 Acknowledgements The Bauer Binaural Crossfeed effect in the ADI-2 DAC was inspired by Boris Mikhaylov’s bs2b implementation. Trademarks All trademarks, registered or otherwise, are the property of their respective owners.
35. Declaration of Conformity 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 RL2014/30/EU, and European Low Voltage Directive RL2014/35/EU. FCC This device complies with Part 15 of the FCC Rules.
