Rme ADI-2 PRO User Manual
32 Bit / 768 kHz
Hi-Res Audio
SteadyClock
2 Channels Analog / Digital Converter
4 Channels Digital / Analog Converter
2 Extreme Power Headphone Outputs
User’s Guide
ADI-2 Pro
Conversion done right
™
III
AES / ADAT / SPDIF Interface
32 Bit / 768 kHz Digital Audio
USB 2.0 Class Compliant
Digital Signal Processing
Advanced Feature Set
SyncCheck
™
General
1 Introduction ...............................................................5
2 Package Contents .....................................................5
3 System Requirements ..............................................5
4 Brief Description and Characteristics.....................6
5 First Usage - Quick Start
5.1 Connectors and Controls ........................................7
5.2 Quick Start ..............................................................8
5.3 Operation at the unit................................................8
5.4 Overview Menu Structure .......................................9
5.5 Playback................................................................10
5.6 Analog Recording..................................................10
5.7 Digital Recording...................................................10
6 Power Supply...........................................................11
7 Firmware Update .....................................................11
8 Features Explained
8.1 Extreme Power Headphones Outputs ..................12
8.2 Dual Phones Outputs............................................13
8.3 5-band Parametric EQ ..........................................13
8.4 Bass / Treble .........................................................14
8.5 Loudness...............................................................14
8.6 SRC (Sample Rate Conversion) ...........................15
8.7 Crossfeed..............................................................15
8.8 DSP Limitations.....................................................16
Basic and Stand-Alone Operation Details
9 Operation and Usage ..............................................18
10 Front Panel Controls
10.1 Keys .....................................................................18
10.2 Encoders ..............................................................18
11 VOL ...........................................................................19
12 I/O
12.1 Analog Input
12.1.1 Settings ........................................................19
12.1.2 Parametric EQ..............................................20
12.2 Main Output 1/2
12.2.1 Settings ........................................................21
12.2.2 Bass/Treble ..................................................22
12.2.3 Loudness......................................................23
12.3 Phones Output 3/4 ...............................................23
13 EQ .............................................................................24
14 SETUP
14.1 Options
14.1.1 Hardware/Diagnosis.....................................26
14.1.2 Clock ............................................................27
14.1.3 Device Mode ................................................27
14.2 Load/Store all Settings .........................................28
15 Meter Screens
15.1 Global Level Meter ...............................................29
15.2 Analyzer ...............................................................29
15.3 State Overview .....................................................30
15.4 Dark Volume ........................................................31
16 Warning Messages..................................................31
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17 Modes
17.1 Auto...................................................................... 33
17.2 Preamp ................................................................ 34
17.3 AD/DA Converter .................................................35
17.4 USB...................................................................... 36
17.5 Digital Through..................................................... 38
17.6 DAC ..................................................................... 39
18 Balanced Phones Mode.......................................... 40
19 DSD Operation
19.1 General ................................................................41
19.2 Direct DSD ........................................................... 41
19.3 DSD Playback...................................................... 42
19.4 DSD Record ......................................................... 42
19.5 DSD Level Meter.................................................. 43
19.6 Beyond… .............................................................43
Inputs and Outputs
20 Analog Inputs .......................................................... 46
21 Analog Outputs
21.1 General ................................................................46
21.2 Line Out TS 1/2.................................................... 47
21.3 Line Out XLR 1/2 ................................................. 47
21.4 PH Out 1/2 ...........................................................47
21.5 PH Out 3/4 ...........................................................48
22 Digital Connections
22.1 AES...................................................................... 48
22.2 SPDIF ..................................................................49
22.3 ADAT ...................................................................50
Installation and Operation - Windows
23 Driver Installation.................................................... 52
24 Configuring the ADI-2 Pro
24.1 Settings Dialog..................................................... 53
24.2 Clock Modes - Synchronization ........................... 54
25 Operation and Usage
25.1 Playback .............................................................. 54
25.2 DVD Playback (AC-3 / DTS)................................ 55
25.3 Multi-client Operation ........................................... 55
25.4 Multi-interface Operation ..................................... 55
25.5 ASIO .................................................................... 56
26 DIGICheck Windows ............................................... 56
Installation and Operation – Mac OS X
27 General..................................................................... 58
27.1 Configuring the ADI-2 Pro.................................... 58
27.2 Clock Modes - Synchronization ........................... 59
27.3 Multi-interface Operation ..................................... 59
28 DIGICheck Mac........................................................ 59
User’s Guide ADI-2 Pro – v 1.91
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Installation and Operation – iOS
29 General .....................................................................62
30 System Requirements ............................................62
31 Setup ........................................................................62
32 Supported Inputs and Outputs ..............................62
Technical Reference
33 Technical Specifications
33.1 Analog Inputs .......................................................64
33.2 Analog Outputs ....................................................64
33.3 Digital Inputs ........................................................65
33.4 Digital Outputs......................................................66
33.5 Digital ...................................................................66
33.6 General ................................................................66
33.7 Connector Pinouts................................................67
34 Technical Background
34.1 Lock and SyncCheck ...........................................68
34.2 Latency and Monitoring........................................69
34.3 Balanced Phones Mode .......................................70
34.4 Emphasis .............................................................72
34.5 Noise Level in Hi-Speed Modes...........................73
34.6 SteadyClock .........................................................74
34.7 AD Filter Curves ...................................................76
34.8 DA Filter Curves 44.1 kHz ...................................76
34.9 DA Impulse Responses .......................................77
34.10 AD Impulse Responses .......................................78
34.11 Frequency Response Measurements..................79
34.12 Loudness..............................................................79
34.13 Total Harmonic Distortion Measurements ...........80
34.14 Extreme Power Charts.........................................81
34.15 Phones Distortion Comparison ............................82
34.16 Impedance based Level Meters PH 1-4 ..............82
34.17 USB Audio (Windows) .........................................83
34.18 ADI-2 Pro as Hardware I/O for Measurements....84
34.19 Operation in the Hi-Fi Environment......................86
34.20 Digital Volume Control .........................................89
34.21 Bit Test .................................................................91
Miscellaneous
35 Accessories .............................................................94
36 Warranty...................................................................94
37 Appendix ..................................................................95
38 Declaration of Conformity ......................................96
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User’s Guide ADI-2 Pro - v 1.91
1. Introduction
RME’s ADI-2 Pro is a true milestone in many ways. Looking at the multitude of AD/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.
And while many of those devices claim to use the latest state-of–the–art whatsoever converter
chip, serious magazines and RME staff were repeatedly disappointed to find that in the end the
stellar technical data published in ads and datasheets were nowhere to be found.
With the ever growing popularity of headphones and latest AD/DA chips pushing technical data
further, the time was right for a new RME gem. A unit with the industry’s biggest footprint per
feature ratio, with specs that are as real as RME‘s reputation, a feature set that is unheard of,
useful features that for unknown reasons no one else implemented, and two extremely powerful
headphone outputs, that will be your new reference in accuracy and dynamic range.
Here it is – the ADI-2 Pro, the little wonder, a host of devices all put together into one unit, with
a simple and mostly automated way of using it right out of the box:
x A high-end AD/DA converter in professional studio quality
x A double headphone amplifier in true high-end quality
x A USB DAC like no other - the most versatile and capable one around
x A high-end AD/DA frontend and headphone amp for iPad and iPhone
x An AD/DA frontend for measurement systems at up to 768 kHz sample rate
x A multi-format converter (AES, SPDIF, ADAT) with monitoring
x An SPDIF/ADAT playback system
x A DSD record and playback solution
All there is left to say now is: Enjoy!
2. Package Contents
x ADI-2 Pro
x Manual
x External switched power supply, lockable connector, DC 12 V 24 W
x Power cord
x Digital breakout cable AES/SPDIF (BO968)
x Quick start guide
3. System Requirements
General:
x Power supply 12V DC, 1.5 A or up
For computer based operation:
x Windows 7 or up, Intel Mac OS X (10.6 or up)
x 1 USB 2.0 port or USB 3 port
x Computer with at least Intel Core i3 CPU
For iOS based operation:
x iPhone or iPad with iOS 7 or up
x Dock or Lightning to USB adapter
User’s Guide ADI-2 Pro – v 1.91
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4. Brief Description and Characteristics
The ADI-2 Pro is a 2-channel analog input to digital and 4-channel digital to analog output converter in a half-rack (9.5") enclosure of 1 U height. Latest 32 bit / 768 kHz converters offer up to
124 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. A
powerful DSP adds all kinds of useful audio processing, including 5-band parametric EQ, fast
Bass/Treble adjustment, Crossfeed, and a new concept in Loudness sound control.
Operation is quick and easy through 3 encoders with push button function and 4 more buttons
to access dedicated menus. The unit remembers all current settings, even the menu position.
Additionally the unit’s whole setup as well as equalizer settings can be stored under individual
names.
A high resolution IPS panel for the graphical operation surface eases operation even more, and
displays further functions provided by the DSP, namely Peak level meters, a 30-band analyzer
in DIGICheck biquad filter technology, and a State Overview screen listing the current states of
SPDIF, AES, USB and clock.
The digital inputs SPDIF coaxial (or optical) and AES operate simultaneously. An additional
Sample Rate Converter decouples the SPDIF or AES clock for even simpler setups, and also
supports up- and down-sampling of the input signals. SPDIF optical also supports 2 channels of
ADAT operation, at up to 192 kHz.
When used as USB interface, the Class Compliant UAC 2 mode can be set to Stereo or Multichannel. Multi-channel mode turns the ADI-2 Pro into a 6 channel (Analog 1/2, AES, SPDIF)
record and 8 channel (Analog 1/2/3/4, AES, SPDIF) playback audio interface, that even works
as iPad front-end up at up to 192 kHz sample rate. In stereo mode sample rates up to 768 kHz
are supported, for high resolution recordings or PCM, DXD and DSD record/playback.
The servo balanced analog inputs and dedicated balanced and unbalanced outputs are fitted
with both XLR and 1/4" TRS/TS jacks. The unit uses a fully balanced and DC-coupled circuit
design, for highest phase accuracy at lowest roll-off. The only capacitors in the whole signal
path, non-polar MUSE audio capacitors from Nichicon, reside directly at the input of the unit
(DC protection).
The two Extreme Power headphone outputs provide reference sound and headroom. RME’s
Advanced Balanced mode not only adds balanced phones operation to the feature list, but also
premiers a new concept on improving the balanced mode even further.
To maintain the full dynamic range within the best operating level, discrete 4-stage reference
level settings were realized for maximum dynamic range (+4, +13, +19, +24 dBu). Also available are 0 to +6 dB digital trim for fine input sensitivity adjustment in steps of 0.5 dB.
The ADI-2 Pro supports all sample rates between 32 kHz and 768 kHz. Furthermore, RME's
SteadyClock III guarantees exceptional performance in all clock modes. Thanks to a highly
efficient jitter suppression, the AD- and DA-conversion always operates on highest sonic level,
being completely independent from the quality of the incoming clock signal.
The ADI-2 Pro shines in both studio and home usage. Its click- and noise-free on/off operation
and a comfortable, illuminated standby button add to the soft, modern desktop design.
Mobile and galvanically separated usage is possible through a 12V connector for easy battery
connection.
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User’s Guide ADI-2 Pro - v 1.91
5. First Usage – Quick Start
5.1 Connectors and Controls
The front of the ADI-2 Pro 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 1/2 and 3/4 feed two phones outputs via two independent Extreme Power
driver circuits, optimized for both high and low impedance headphones. Their unbalanced output signal is of highest quality. With 120 dBA SNR there is no audible hum and noise at those
outputs.
In case a phones output is to be used as line output, an adapter TRS plug to RCA phono plugs,
or TRS plug to two TS plugs is required.
The rear of the ADI-2 Pro has 2 servo-balanced analog inputs on combo XLR/TRS sockets, 2
TS sockets as unbalanced outputs, 2 XLR sockets as balanced outputs, TOSLINK optical I/O, a
USB socket, and a lockable power socket. An included breakout cable is connected to the DB-9
socket and provides AES I/O via XLR and SPDIF coaxial I/O via RCA.
The ADI-2 Pro has two analog line inputs that can operate with levels up to +24 dBu. The electronic input stage uses a servo balanced design which handles unbalanced and balanced signals correctly, automatically adjusting the level reference.
When using unbalanced cables with the XLR inputs, pin 3 of the XLR jack should be connected to ground. Otherwise noise may occur, caused by the unconnected negative input of
!
the balanced input.
The analog inputs 1/2 include 6 dB digital gain control via DSP, and a choice of +4 dBu, +13
dBu, +19 dBu or +24 dBu as reference level, performed in the analog domain.
The short circuit protected, low impedance XLR line outputs do not operate servo balanced! When connecting unbalanced equipment via XLR, make sure pin 3 of the XLR
output is not connected. A connection to ground might cause a decreased THD (higher
!
distortion) and increased power consumption!
Optical I/O (TOSLINK): The unit automatically detects SPDIF or ADAT input signals. The optical output can operate as ADAT or SPDIF output, depending on the current setting in the Setup
menu (Options, Hardware/Diagnostics). Note that only channels 1/2 from the ADAT stream can
be accessed. SMUX and SMUX4 (up to 192 kHz) are still supported.
USB 2.0: Standard USB socket for connection to the computer. The ADI-2 Pro operates as
Class Compliant device, in either 2-channel or 8-channel mode (configured in Setup). It can be
directly used with Mac OS X and iOS (iPad, iPhone). For Windows the RME MADIface series
driver adds WDM and ASIO.
Socket for power connection. This socket supports locking type jacks as found on the included
RME DC power supply. After inserting the connector carefully turn it by 90° so that it locks.
User’s Guide ADI-2 Pro – v 1.91
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5.2 Quick Start
Connect the unit to the included power supply and push the Standby button to start. The ADI-2
Pro ships with Basic Mode Auto activated (SETUP – Options – Device Mode – Basic Mode).
The input selection for SPDIF (coaxial or optical), and the source selection for Phones Out 3/4
are also set to Auto, the SRC is activated for the SPDIF input. With Auto active the unit will turn
into different modes depending on connected cables:
x Preamp: Analog in to Analog out (internal digital out to in). This mode is active when no digi-
tal input signal and no USB is detected.
x AD/DA: Converter Mode, analog in to all digital outs, digital in to all analog outs. This mode
becomes active as soon as a digital signal is attached. This signal will also become the signal source. In case more than one digital signal is found the user has to manually select the
source to be monitored. The SRC is active as default and assigned to SPDIF. Clock mode is
slave to AES in, but will adapt to the detected source (Auto).
x USB: or interface mode (also USB DAC). If USB is detected all inputs are routed to USB, all
outputs are fed from USB. USB has priority over the converter mode. In Setup the unit can
be configured as 2- or 8-channel device. In most cases 2-channel will be the better choice.
USB can be manually overridden by selecting a different mode. This will change the I/O routing,
but not disable USB itself. All inputs are still available via USB, outputs 3/4 can playback USB.
In all modes except Basic Mode DAC output PH 3/4 is freely configurable, any possible source
can be monitored independently from Outputs 1/2.
The unit remembers all settings, and loads these automatically when it is switched on again. To
switch off, press the Standby button for at least 0.5 seconds.
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 selected output. Pushing the big
Volume knob changes the volume setting between Outputs
1/2 and 3/4. The status bar at the bottom of the display
shows the current dB value of both volume settings. A white
rectangle around it (marker) indicates which volume the big
encoder is currently set to control.
The header shows the currently selected output as well as
hardware reference level (Ref Lev, see chapter 12.2.1).
The EQ is set up either directly within the I/O menu structure (key I/O, turn encoder 2 to access
Settings, Parametric EQ, Bass/Treble and Loudness), or via the graphical EQ screen which is
shown after pressing the EQ key. In this screen the cursor has three positions: top*, the EQ
parameter line below the response curve, and filter selection type for band 1 and 5 (Peak, Shelf,
Low/High Cut). The cursor is moved up or down by pushing encoder 1 or 2. When in the EQ
parameter line, all values are no longer grayed out. In this state the big encoder steers Gain,
encoder 1 Frequency, and encoder 2 Quality factor. This way the EQ is extremely fast set up
and edited.
The graph has 5 different colors matching the 5 bands that can be adjusted. If the line is just
grey the EQ is disabled (bypass). The EQ can be enabled in the second menu which comes up
by pushing the EQ key a second time.
*(shown by a 1 beside the current channel. Turning encoder 1 will change to the EQ settings of the other channels)
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User’s Guide ADI-2 Pro - v 1.91
The unit has several informative screens on the top level. These are Global Level Meters,
Analyzer Input, Analyzer Output 1/2, Analyzer Output 3/4, State Overview and Dark Vol-
ume. Change between them by pushing encoder 1 or 2 whenever any of them is displayed. To
quickly call them up simply press any of the 4 buttons several times.
In all these screens turning encoder 1 and 2 brings up the quick access to Bass and Treble,
with ± 6 dB maximum boost/cut.
5.4. Overview Menu Structure
User’s Guide ADI-2 Pro – v 1.91
9
5.5 Playback
In the audio application being used, the ADI-2 Pro must be selected as output device. It can
often be found in the Options, Preferences or Settings menus, as Playback Device, Audio De-
vices, Audio etc. After selecting a device, audio data is sent to an analog or digital port, depend-
ing on which has been selected as playback device.
Increasing the number and/or size of audio buffers may prevent the audio signal from breaking
up, but also increases latency i.e. output is delayed.
5.6 Analog Recording
For recordings via the analog inputs the corresponding record device has to be chosen.
Channels 1/2 of the ADI-2 Pro have digitally controlled gain and four hardware-based reference
levels. The digitally controlled gain offers a gain setting in steps of 0.5 dB within a range of 0 dB
to +6 dB, for fine-tuning the input sensitivity. The four hardware-based Reference Levels allow a
coarse adaption to the current source signal. The ADI-2 Pro has global as well as channel level
meters. Setting the correct Ref Level to avoid clipping/overload is easy to do.
The combo XLR/TRS sockets are designed for line signals. Sources that require higher input
impedances, like guitars, need an additional impedance buffer in front of the ADI-2 Pro.
5.7 Digital Recording
The easiest way to perform digital recordings with the ADI-2 Pro is to set the SRC to the currently used input (SPDIF or AES), then set the Clock to INT(ernal) and the desired sample rate
– then start recording.
The SRC serves as clock decoupler. When not using the SRC, the ADI-2 Pro must be in total
Sync to the external digital device, as either master or slave. Taking this into account, RME
added a comprehensive I/O signal status display to the ADI-2 Pro, showing sample frequency,
lock and sync status in the State Overview screen and the bottom status bar.
The sample frequency shown in the State Overview screen is useful as a quick display of the
current configuration of the unit and the connected external equipment. If no sample frequency
is recognized, it will show - - (No Lock).
This way, configuring any suitable audio application for digital recording is simple. After connecting it the ADI-2 Pro displays the internal and external sample rate. This parameter can then
be changed in the application’s audio attributes (or similar) dialog.
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User’s Guide ADI-2 Pro - v 1.91
6. Power Supply
In order to make operating the ADI-2 Pro as flexible as possible, the unit has a universal DC
input socket, accepting voltages from 9.5 Volts up to 15 Volts. An internal switching regulator of
the latest technology with high efficiency (> 90%) prevents internal hum noise by operating
above audible frequencies. Internally the switching regulator is followed by standard linear regulators, followed by super low-noise linear regulators. Therefore the ADI-2 Pro achieves its technical specs even with less optimal power supplies. Or in other words: the choice of power supply is not critical.
Still the unit includes a high-quality switching power supply, 12 V / 2 A, which not only accepts
any mains voltage between 100 V and 240 V (usable world-wide), but is also fully regulated
against voltage fluctuations and suppresses line noise. Additionally it only weights 150 g in spite
of its high power of 24 Watts.
The DC input of the ADI-2 Pro also allows for the use of a rechargeable lead-battery or LiPo
instead of a power supply, for completely independent mobile operation and ground isolation. A
matching connection cable (power jack to terminals 6.3 mm) is available from RME. Special
power banks in the range of 10,000 mAh and up can be found equipped with a 12 V output.
These offer a perfect solution for mobility as well as ground isolated operation, for small money.
7. Firmware Update
The ADI-2 Pro 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 Pro 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. It displays
the current revision of the ADI-2 Pro
firmware, and whether it needs an
update or not. If so, then simply press
the 'Update' button. A progress bar will
indicate when the flash process is
finished (Verify Ok).
After the update the ADI-2 Pro needs
to be reset. Push the standby button to
switch it off for 5 seconds.
When the update unexpectedly fails
(status: failure), the unit's Safety BIOS
will be used from the next boot on, the
unit stays fully functional. The flash process should then be tried again.
The flash process does not affect user data like sample rate choices, EQ settings or Setups.
Returning to Factory State
In case a total reset is desired: hold encoder 1 and the VOL button pushed while turning on the
unit. This will reset all memory to factory default. Setups and EQ Presets stored by the user will
not be deleted.
User’s Guide ADI-2 Pro – v 1.91
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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).
Limiting the current makes a lot of sense. It is needed to control the internal power supply, to
not fully overdrive (and destroy) weaker headphones, and prevents malfunction at short-circuit
state. The Extreme Power output stage acts like a small power amplifier, so it got a similar feature set: a relay that mutes and interrupts the connection to the phones, a DC sensing circuit to
prevent DC at the output (DC destroys your precious phones already when the rated watts are
not even closely reached!), and an over-current protection circuit that will notice when a shortcircuit causes too high current, preventing the output stage to get destroyed. In light of the malicious treatment of this output stage during development it needs to be mentioned that it can not
be destroyed by a short-circuit at the output nor by overheating. Still some extra safety won’t
hurt, and the over-current protection circuit got in.
A goal during development was to build a headphone amp that not only reaches very low THD
un-loaded (the typical way of measuring it), but very low THD values with a 32 or 16 ohm realworld load. This was achieved in the new Extreme Power headphone driver output stage. It
uses 6-fold spread power technology, improved thermal conductivity and a special super-low
distortion driver design. The result is THD below -110 dB at 32 Ohm load even near full output
level (clipping), the same SNR as the DAC provides (120 dBA), an output impedance of only
0.1 Ohms, totally stable operation, and a frequency response from 0 Hz up to 80 kHz, with just
0.5 dB decrease at the top end. The result: No audible hum, noise or distortion, fully transparent
and crystal clear sound at any volume setting, for any personal taste in any application.
And there is more. The headphone sockets of the ADI-2 Pro have sensor contacts. The unit
always knows when a headphone jack is inserted or removed. The DSP uses this information
for several superior, partly never-seen before features. For example when inserting the headphone jack into Ph 3/4, the ADI-2 Pro activates the mute relay after half a second, then the DSP
ramps up the volume slowly from lower level to the last used state. Comfortable? Luxurious?
Yes, but the main reason for it was to give the user a chance to react. Extreme Power headphone outputs set to full output level, music already playing at full level, inserting the phones,
and the moment the relay switches on the doctor is called, diagnosing sudden deafness - this
should and can not happen with the ADI-2 Pro. When the volume is ramped up one has the
time to either quickly set the phones off, unplug the phones again, or to grab the Volume knob
to quickly turn it down.
To guarantee that the Volume knob will be set to control the correct outputs in that moment, the
DSP also sets the Volume knob automatically to the output where phones had been plugged in.
And even returns the setting when the phones are unplugged again.
This is just an example of how intelligent and elaborate the control logic of the ADI-2 Pro has
been implemented. There are lots of such functions and features that might even stay unnoticed, making the unit behave fail-proof as well as easy to operate.
But isn’t +22 dBu, or Hi-Power as it is called in the menu, much too loud for modern phones?
That depends. There are still phones that need higher levels. Music can be low in volume but
consume a lot of power, especially with lots of sub-bass. And lots of headroom is always nice to
have. Typically with Hi-Power off, which equals +7 dBu maximum output level, modern music
and modern headphones, Hi-Power is mostly not needed. But you will notice that even with HiPower active, which requires to use a volume setting 15 dB lower as usual, the sound stays the
same, and there is no audible noise or hum at the phones output (provided the source is clean,
of course). So even at a Volume setting of -40 dB the ADI-2 Pro delivers perfect sound quality,
being a no-brainer in daily use as how to set it.
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User’s Guide ADI-2 Pro - v 1.91
8.2 Dual Phones Outputs
Many features and design decisions on the ADI-2 Pro come from personal usage and experience. For example when comparing headphones: it turns out to be very difficult when having
just one headphone output. Changing the phones on the head is already a disrupting process
which hinders easy comparison, but without proper level adjustment first, and the need to unplug one and to plug the other, comparisons are only possible for coarse differences. At RME
we are used to compare headphones connected to a Fireface UFX or 802. These exceptional
audio interfaces have two independent phones outputs. The included TotalMix FX, a DSP
based mixing engine, allows to route the same audio signal to both outputs, with individual volume settings, and no need to unplug / plug anything. So if one phone is too low in volume it is
simple to raise it, or lower the other one, to get them on the same volume, making a comparison
much easier.
The ADI-2 Pro has two stereo DA-converters to similarly provide two independent and individual
phones outputs. Adding a third DAC for the line outputs would raise cost, space and effort tremendously, while listening on two phones at the same time or comparing phones this way is a
seldom task. Therefore one phones output, labelled PH 1/2 on the front, shares the main (rear)
output signal. Although this phones output reaches the same technical specs as PH 3/4, and
also has the exact same Extreme Power output stage, it is considered the ‘spare’ Phones output for comparing phones, dual phones usage, and balanced phones operation – or just use it
as another unbalanced line output. The main Phones output, which is independent from the rear
outputs, is PH 3/4. For most users it will be the only output ever needed and used. And because
it is the most often used one it was intentionally moved away from the Volume knob to ease
operation, resulting in an unusual arrangement with PH 3/4 left and PH 1/2 right.
As explained a major reason to have not only two, but two independent phones outputs is that it
offers a much better way to compare headphones. But there is more to it, see next chapter.
8.3 5-band Parametric EQ (PEQ)
Comparing headphones with the Fireface UFX and 802 comes with another, big advantage:
TotalMix FX controls a 3-band parametric equalizer (PEQ), again independent for both outputs.
So if one phone has too much or too little bass, it’s easy to reduce or increase lower frequencies so the phones become more similar. This makes it much easier to hear the basic, but finer
differences in the phones sound signature.
Having worked extensively with this luxurious double output solution, there is no question why
the ADI-2 Pro got two fully independent, identical ‘Extreme Power’ headphone outputs, and
individual equalizers for both outputs. This is indeed the premium way to compare headphones
seriously as well as efficiently.
While no equalization as well as listening only straight linear has been a mantra for many years,
research has proven that no ears are identical, and that especially in near-field listening (with
phones) the biological differences alone make individual equalization mandatory. No two pairs
of ears hear the same thing, that’s a fact. Additionally personal taste makes people like different
sound signatures, which can easily be copied or made more similar (equalized…) on different
headphones using a good EQ. The advantages of using an EQ outweigh any alleged disadvantages - which so often turn out to be wrong at closer inspection.
Having used PEQ to linearize as well as to better meet personal taste with a variety of headphones, RME found 5 bands of parametric EQ to be the best balance between occupied DSP
resources and efficient sound treatment. While it is true that on some phones rebuilding an exact response curve needs more than 5 bands, one quickly realizes that very narrow peaks and
notches make no audible difference when compensating them. Their acoustical energy is too
low to get audible. Ignoring those narrow peaks/notches and only taking care of deviations that
require a quality factor of 3 or below, the 5 band parametric EQ turns into a very efficient tool
even for problematic phones.
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This is one of the many major features that can’t be found on any similar device: a high-quality
5-band parametric EQ, usable at up to 768 kHz sample rate, easy to set up and adjust, with a
graphical display showing the resulting curve, and multiple storage places including individual
naming. So whatever EQ setting you need, it is loaded and modified quickly. And there is not
only one, but three such EQs, separately for the analog inputs, and both stereo analog outputs.
On a related topic: These days many people suffer from hearing loss in varying degrees. No
matter if it is biological, from abuse or an accident - hearing impaired is a plague of modern
times. And – no surprise when thinking about it – it never affects both ears identically. The number of people having one sided hearing problems is huge, but they have learned to live with an
industry that totally ignores them. Although the solution is as simple as logical – have the EQ be
adjustable independently for left and right. Basically digital EQs are calculated this way, the
common controls are just for making it easier to operate. The ADI-2 Pro includes an option
called Dual EQ – a heaven send feature for many, for sure.
Of course a 5-band parametric EQ is also suitable for speaker and room correction, another
application where separate EQ left/right setups are necessary. Using the ADI-2 Pro as DAC for
the main monitors will benefit from this and all the other typical RME features available on all
analog I/Os: Phase and Mono in various options, Width and M/S Processing.
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. Producers and mastering engineers not only have their own taste, they also sometimes fail in providing a mix that is on an average sound level compared to others. In that moment a quick turn on the two ADI-2 Pro’s small encoders will make the music sound perfect.
These Bass and Treble controls are limited to ± 6 dB. Everything exceeding such values should
be handled by the EQ, and/or calls for better speakers/phones. The corner frequency and quality factor of Bass and Treble is user-adjustable in the display’s menu, making this feature even
more useful. Adapt it to meet your speakers/phones or your personal taste – it will greatly improve your pleasure in listening to music again.
8.5 Loudness
Another legacy of HiFi amplifiers: there has not been a single one missing a feature called
Loudness. It tries to address the changes in frequency-dependent hearing sensitivity over dif-
ferent volume levels. If one listens to music loud, then drops the level by at least 20 dB, sound
loses punch and glitter. HiFi amps tried to fight this effect by adding more bass and treble the
lower the volume was set. Unfortunately that never worked as intended, and just became an
additional bass/treble booster. Reason: the manufacturer of the HiFi amp could not know what
volume any position of the volume knob equals at the customer’s home. Room size, room
dampening and efficiency of the used speakers are all unknown.
But the effect of loss in perceived sound exists (read about the Fletcher-Munson curves), and
can be easily reproduced with any serious gear by comparing normal volume and DIM state
(usually -20 dB). The ADI-2 Pro offers Loudness for both analog stereo outputs, and probably is
the first time that Loudness works as intended. The user can decide how much maximum gain
in Bass and Treble should occur at lower volume settings. The user also sets the Low Vol Reference, where maximum gain is achieved. After extensive tests a 20 dB range has been defined as range for maximum gain to no gain while increasing volume. That seemed to be the
perfect definition of the range that needs to be addressed by Loudness.
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Here is an example on how it works: the user’s typical lowest level listening volume is at -35 dB
at the unit. This value is now set by the user as Low Vol Ref in the Loudness menu. Then Bass
and Treble Gain can be set between 0 and +10 dB. Default is +7 dB for both. Increasing the
volume by turning the Volume knob causes the gain in Bass and Treble to be lowered smoothly
over a range of 20 dB. So when Volume is set to -15 dB, the music is not only quite loud, but
Loudness’ Bass and Treble are then at 0 dB gain. See chapter 34.12 for graphs.
No matter how sensitive the connected phones or speakers are, no matter how much increase
in Bass and Treble are desired – with the ADI-2 Pro one can finally adjust it to meet the personal hearing and taste. Loudness finally works as it should have worked from the start - another unique feature in the ADI-2 Pro.
8.6 SRC (Sample Rate Conversion)
The ADI-2 Pro includes an asynchronous stereo sample rate converter (SRC). A SRC allows a
conversion of the sample rate in real-time. The converter used in the ADI-2 Pro operates practically without loss of signal quality, so no audible artefacts or noise is added. In fact, the SRC
works so well that we could recommend to just leave it on at all times, thus eliminating all clock
problems right from the start. Which is the case for the SPDIF input in Auto mode.
The SRC offers a maximum conversion rate of 1:7 or 7:1, respectively. Thus, 192 kHz can be
converted to any sample rate down to 32 kHz, and 32 kHz can be converted to any frequency
up to 192 kHz. Higher sample rates than 192 kHz are not supported.
An SRC not only converts sample rates, it also serves as a clock decoupler. With SRC active,
even non-synchronizable devices (CD-players, DAT machines, etc.) can be used in a setup of
digital devices, just as if they were externally synchronized. The SRC decouples input and output clock and sets the output clock to the common reference, thus allowing the combination of
different clock-sources. For example having the ADI-2 Pro synchronized to an AES signal, a CD
player connected to SPDIF input can only be used when the SRC is set to SPDIF. It then decouples the clock of the non-synchronizable CD player, preventing clock problems and drop
outs. As the incoming clock phase is no longer fixed when the SRC is activated, the SPDIF
Sync state in the State Overview screen will always show lock.
When using the internal clock, every SRC also works as a jitter killer. However, the ADI-2 Pro is
equipped with SteadyClock III, thus operating as perfect jitter killer with any clock source. However again, a jittery input signal might degrade the quality of the sample rate conversion. The
ADI-2 Pro therefore has a second SteadyClock exclusively for the current SRC input signal to
make the sample rate conversion process as reliable and transparent as possible.
A SRC can also be used to upsample audio. A 44.1 kHz source can be converted to 192 kHz in
real-time and thus played back with the DAC set to 192 kHz. The usefulness of this process is
questionable. There is zero content added, so the exact same audio is played back. The only
change is that the DAC's oversampling filters are moved far out of the audible range. But even
at 44.1 kHz the ADI-2 Pro’s filters are inaudibly high, and the process of sample rate conversion
also uses those lower filters in its first conversion step.
8.7 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 Pro 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. It uses the Bauer Binaural method, with five selectable
strengths of narrowing the upper frequencies. This advanced method, which also includes a
small delay and correction of the frequency response, works quite well, and is another useful
addition as well as a unique feature on a device like the ADI-2 Pro.
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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 Pro. 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. The DSP in the ADI- 2 Pro performs:
Bass/Treble and Loudness for 6 channels
5-band parametric EQ for 6 channels
Standard phase functions for 6 channels
Crossfeed for 4 channels
30-Band bi-quad bandpass filter spectral analyzer
Peak Level meters for all channels
Display rendering
Volume control on 4 channels
Several controller-like functions, like volume ramp-up, mute, signal routing control etc.
Balanced Phones mode control
DSD to PCM conversion (for level meters)
At 48 kHz that is no big deal, at 192 kHz it already needs efficient coding and a better DSP chip.
But at 768 kHz you need a DSP with 4 times the power of the ‘better’ one. Therefore there is no
way around disabling some functions at higher sample rates. Fortunately those limitations have
only small impact in real-world usage:
x At sample rates 352.8 kHz and up the Bass, Treble and Loudness function is deactivated.
The number of available EQ channels is reduced to 2 (1 x stereo). EQ can still be used with
Analog Input, Main Output 1/2 or Phones Out 3/4, but only one of these.
x At sample rates 705.6 kHz and up Crossfeed or EQ (1 x stereo) can be active, not both at
the same time.
The high sample rates available in the ADI-2 Pro also exceed the capabilites of the digital I/Os.
Both AES and SPDIF are limited to 192 kHz, and there is no way around it (except a special,
one channel SMUX mode, see chapter 14.1.2, Setup Clock). Therefore all higher sample rates
are only usable analog and in USB mode. And in iOS mode when using an iPad/iPhone with an
app that supports such high sample rates (Neutron, Onkyo HF-Player etc.).
DSD comes with its own limitations. DSD is a 1 bit stream of data that can not be processed
digitally. There is no Bass, Treble, Loudness, EQ etc. possible at all. The volume control is no
longer done by the DSP, but the DAC chip, which converts DSD into PCM to be able to offer
level (volume) modification. You won’t notice that, volume operation at the ADI-2 Pro is seamless and behaves identical in any mode. The DSP now performs an additional DSD to PCM
conversion, to be able to show the audio signal on the level meters and the Analyzer – a unique
feature of the ADI-2 Pro.
Even more extreme is DSD Direct. If activated (SETUP, Options, Device Mode), the DSD signal is not converted to PCM within the DAC, therefore there is no volume control at all – except
for the analog reference levels, which can be used to set the coarse output level/volume. Left
with no volume control, the ADI-2 Pro intentionally deactivates the headphone output 1/2 in
DSD Direct mode – the analog signal is only available at the rear outputs. Phones Out 3/4 continues to work as it is independent and uses normal DSD mode or PCM, according to what
source signal it receives.
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User’s Guide
ADI-2 Pro
Basic and Stand-Alone Operation Details
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9. Operation and Usage
General operation and usage of the ADI-2 Pro are explained in chapter 5.2, Quick Start, and
chapter 5.3, Operation at the unit.
The ADI-2 Pro ships with Basic Mode Auto activated. In this mode the unit will automatically
reconfigure itself depending on the connected cables, offering quick, easy and intuitive operation:
¾ No digital input, no USB = Preamp mode
¾ Digital input signal = AD/DA converter mode
¾ USB connected = USB mode (USB interface operation)
These modes are explained in detail in chapter 17. The current mode is also shown for 2 seconds (Info Message) whenever it changes, and one time after power-on.
State Overview is especially useful to check the state of digital input signals as well as the current settings with USB. It also displays several warning messages which might explain why
currently no sound is audible. See chapter 15.3 for details.
The following chapters explain all the controls and menu items in detail.
10. Front Panel Controls
10.1 Keys
The four back-lit keys offer quick access of important parameters within the menu structure.
After pressing one of the four keys the corresponding menu is shown in the display. The unit
remembers the last selection per key, so re-visiting a formerly changed parameter is easy. To
leave the menu push the same key a second time, or any other key two times. The display will
revert to the level meter screen that was active before entering the menu.
10.2 Encoders
The encoders can be turned endlessly, but also pressed, adding a push button function. The
current functionality of all encoders is shown in the display. The big Volume knob usually controls volume for outputs 1/2 or 3/4. The current assignment is indicated in the display’s status
bar by a marker around the volume value.
Turning the small encoders 1 and 2 either changes the current parameter, or moves the selection/cursor horizontally to the next page. Pressing the encoders 1 and 2 moves the selection/cursor vertically, up with 1 and down with 2, as indicated by the arrows in the display.
Example: Press the key SETUP. The menu Setups is now
shown. 1 within the circle on the right side indicates that by
turning encoder 1 more pages are available. Turn encoder 1
left to enter Options. Now turn encoder 2 to scroll
horizontally through all the subpages offered under Options:
Hardware/Diagnosis, Device Mode, Clock. By pressing
encoder 2 the cursor moves down, by pressing encoder 1
back up. On a selected field or entry, 2 to the right indicates
that the current parameter can be changed by turning
encoder 2. Change Clock Source and Sample Rate to see
how easy it is to select and change important settings.
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11. VOL
The VOL key brings up an extended volume screen with
balance control. Pushing the big Volume knob changes the
volume setting between outputs 1/2 and 3/4, which 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
current dB value of both volume settings. A white rectangle
around it (marker) indicates which volume the big encoder is currently set to control.
A push on encoder 1 (B) mutes the current output. The text in the blue field shows Main 1/2 -
muted. A second push exits the mute state.
Pushing the VOL key a second time enters the Dual
Volume screen, showing both volume settings at the same
time. Encoder 1 controls Volume 1/2, encoder 2 Volume
3/4, and the big Volume knob both. This allows to set the
outputs at individual levels, but also to control those
simultaneously. The linked control operates on a relative
base, with individual volumes staying intact when increased
or decreased, even to maximum and minimum.
In the Dual Volume screen, both outputs can be muted by pushing encoder 1 (B) and encoder 2
(T) respectively.
Pushing the VOL key a third time reverts to the level meter screen that has been active before.
Note
: The Dual Volume screen is not available in Balanced Phones mode. Main Out defaults to
Auto Ref Level enabled. The current volume setting is then shown as dBr (dB relative).
12. I/O
The I/O menu has all the settings for the three analog stereo I/Os Analog Input, Main Output 1/2
and Phones Out 3/4. The submenu Parametric EQ mirrors the settings done in the graphical
EQ screen. The submenus Bass/Treble and Loudness as well as some phase functions are
only found on the two analog stereo outputs.
12.1 Analog Input
12.1.1 Settings
Subpage Settings has the following entries:
Ref Level
Sets the reference level for the analog inputs 1/2. Choices
are +4 dBu, +13 dBu, +19 dBu, +24 dBu, referenced to
digital full scale level (0 dBFS).
Auto Ref Level
ON or OFF. Default: OFF. In case of overload Auto Ref
Level will switch the Ref Level to the next higher setting.
This process is repeated until +24 dBu is reached. In case
Trim Gain was active it will be set to 0 dB first.
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Trim Gain
Digital amplification of the input signal between 0 and +6 dB, in steps of 0.5 dB. Main use is to
fine-tune the input sensitivity so that it matches the reference output level of external gear.
Phase Invert
Available settings are Off, Both, Left and Right. Inverts the phase (180°) on the corresponding
channel.
AD Filter
Short Delay Sharp, Short Delay Slow, Sharp, Slow. The analog to digital conversion can be
done using four different filters. Default is SD Sharp, offering the widest and most linear frequency response and lowest latency. SD Slow causes a small drop in the higher frequency
range, but offers a less aggressive (less steep) filter. Sharp and Slow are FIR filters with different impulse responses. See the Technical Reference section for graphs illustrating the results in
frequency response and impulse response.
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.
AD Conversion
PCM or DSD. Default: PCM. DSD will not become active at sample rates below 176.4 kHz.
When selecting DSD the current DSD rate is shown as well. It changes with the chosen sample
rate (SETUP - Options - Clock).
12.1.2 Parametric EQ
Subpage Parametric EQ has the following entries:
EQ Enable
ON, OFF. Default: OFF.
Band 1 Type
Available settings are Peak, Shelf, High Cut and High Pass
(Low Cut). All filters are adjustable from 20 Hz to 20 kHz, at
a Q of 0.5 to 5.0. Cut/Pass have a fixed 12 dB/oct filter
steepness.
Band 2-4 Type
Available settings are Peak and Shelf.
Band 5 Type
Available settings are Peak, Shelf or High Cut. High Cut is adjustable from 200 Hz to 20 kHz, at
a Q of 0.5 to 5.0 and a fixed 12 dB/oct.
Band 1-5 Gain
Available settings are -12 to +12 dB in steps of 0.5 dB.
Band 1-5 Frequency
Adjustable from 20 Hz to 20.0 kHz in steps between 1 Hz and 100 Hz.
Band 1-5 Q
Quality factor is adjustable from 0.5 to 5.0 in steps of 0.1. This equals a bandwidth setting of
2.54 to 0.29.
Subpage Parametric EQ R is only shown with Dual EQ set to On. It has the exact same
entries as listed above.
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12.2 Main Output 1/2
12.2.1 Settings
Subpage Settings has the same settings as listed for Analog Input, plus:
AD/DA Source
The source of the Main Output 1/2 signal is automatically selected based on the current mode:
Preamp mode: Analog inputs 1/2
USB: Playback channels 1/2
Dig Thru mode: current digital input signal
AD/DA converter: current digital input signal
DAC: current digital input signal and clock
The entry AD/DA Source is therefore usually grayed out.
Only in AD/DA and DAC mode the input signal can be
chosen between Auto, SPDIF, AES and Analog. This
allows to choose between all currently attached digital
input signals for conversion to output 1/2.
Ref Level
Sets the reference level for the analog outputs 1/2. Choices are +4 dBu, +13 dBu, +19 dBu, +24
dBu, referenced to digital full scale level (0 dBFS). This setting is also valid for the front output
PH 1/2, with PH 1/2 having 3 dB higher output level. This way the setting +4 dBu becomes +7
dBu output level, +19 dBu becomes +22 dBu at the phones jack. These two settings are therefore identical to Hi-Power Off and On at Phones Output 3/4.
Auto Ref Level
ON, Off. Default: ON. See chapter 21.3 for details.
Mono
OFF, ON, to Left. Default: OFF. The option to Left sends the sum of left and right channel to the
left output only.
Width
Defines the stereo width. 1.00 equals full stereo, 0.00 mono, -1.00 swapped channels.
M/S-Proc
Activates M/S processing. Monaural content is sent to the left, stereo to the right channel.
Crossfeed
OFF, 1, 2, 3, 4, 5. The Bauer stereo to Binaural crossfeed effect emulates speaker playback by
reducing the stereo width in the treble range. Adjustable in five steps.
DA Filter
Short Delay Sharp, Short Delay Slow, Sharp, NOS. The Digital to Analog Converter chip offers
several oversampling filters. Default is SD Sharp , offering the widest and most linear frequency
response and lowest latency. SD Slow causes a small drop in the higher frequency range, but
has a less aggressive (less steep) filter. Sharp and Slow are similar, but have a higher latency.
NOS is the filter with the smallest steepness and therefore affecting treble more than the others,
but offers the best impulse response. See the Technical Reference section for graphs illustrating the results in frequency response and impulse response.
: NOS deactivates the option De-Emphasis.
Note
De-Emphasis
Auto, OFF, ON. Default: Auto. For manually de-/activating the DAC's de-emphasis filter. See
chapter 34.4.
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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. Turning the knob fast increases the steps. It is therefore very easy to quickly jump
from 0 dB to mute by a quick left turn of the knob. At moderate turning speed the changes in dB
follow the intended volume change. Only at slower turning the finest steps will be used.
Balance
Mirrors the balance control in the VOL screen. Adjustable from L 100 (left) through <C> (center)
to R100 (right).A quick turn jumps from L or R to <C> and vice versa.
Mute
Mutes the output. Can also be controlled via the VOL screen and Remap Function Keys.
12.2.2 Bass/Treble
Subpage Bass/Treble has the following entries:
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). Adjustable between -6 dB and +6 dB in steps of 0.5 dB.
Treble Freq
Corner frequency of the shelf treble filter. Adjustable from 3 kHz to 10 kHz in steps of 100 Hz.
Default: 6.5 kHz.
Treble Q
The quality factor of the filter is adjustable from 0.5 to 1.5. Default 0.7.
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12.2.3 Loudness
Subpage Loudness has the following entries:
Enable
ON, OFF. Default: OFF.
Bass Gain
Maximum Bass amplification. Adjustable between 0 dB and
+10 dB in steps of 0.5 dB. Default: +7 dB
Treble Gain
Maximum Treble amplification. Adjustable between 0 dB
and +10 dB in steps of 0.5 dB. Default: +7 dB
Low Vol Ref
Reference level for highest Bass/Treble amplification, referenced to the Volume set in dB. Available range is -90 dB to -20 dB. Default: -30 dB. A volume setting below this point will have
maximum Bass/Treble gain, all volume settings above this point will have lower Bass/Treble
gain. 20 dB above the Low Vol Ref setting the Bass/Treble gain will be zero.
12.3 Phones Output 3/4
Subpage Settings has the same settings as listed for Main Output 1/2, plus:
Source
Default: Auto. The source of the output Phones Out 3/4 can
be chosen manually anytime. Available options are: Auto,
AES, SPDIF, Analog, USB 1/2, USB 3/4. Auto here not only
means current or available signal, but also channels 1/2.
Hi-Power
OFF, ON. Default: OFF. Reference level for 0 dBFS is +7
dBu at the output. With Hi-Power on reference level is 15
dB higher, +22 dBu.
Auto Ref Level
ON, OFF. Default: OFF. See chapter 21.3.
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13. EQ
The key EQ brings up a graphical EQ screen (Bode plot) to
set the EQ quickly and with full overview. It is available on
all analog I/Os. The I/O - Settings submenu Parametric EQ
mirrors the settings done in this screen.
On the top level, turn encoder 1 to change between Analog
Input, Main Output 1/2 and Phones Out 3/4. Turning
encoder 2 will scroll through all 5 bands, as can be seen in
the parameter line. This function allows to see/check/verify
all parameters of all bands quickly, without the danger of
changing any of them.
Push encoder 2 to move the cursor to the parameter line,
with all values shown in white color. It is now possible to
adjust all parameters by turning the three encoders. The
Volume knob changes Gain, encoder 1 Frequency,
encoder 2 Q (Quality factor). All changes are shown in realtime as frequency response curve, making it very easy to
find the desired settings.
To change to the next band push the encoder Volume.
The five bands have different colors to clearly show what is currently selected: band 1 red, band
2 yellow, band 3 green, band 4 light blue, band 5 dark blue.
Band 1 and 5 also allow to set the filter to Peak or Shelf mode, plus Hi Pass/Hi Cut. This function is accessed by pushing encoder 2 so that the cursor moves down to the small filter symbol
in the lower right. It is no longer grayed out. Turning encoder 2 now toggles through the available settings, with the symbol changing according to the selected function.
Another push on encoder 2 changes to the graphical EQ
Preset selection screen. Turning encoder 2 will scroll
through all available EQ presets with the frequency
graphics showing the respective curve, and the parameter
line showing the preset name. In this screen Volume, volume selection and channel selection (encoder 1) are also
available.
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 Pro 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. Reducing the output volume will prevent
any clipping as long as the headroom of 24 dB is not exceeded. In real-world operation that is
always the case, the ADI-2 Pro will not distort internally.
The EQ can cause distortion for the digital outputs when used on the Analog Input. Again the
level meters will clearly show this error condition. Reduce the input’s sensitivity by selecting a
higher Reference Level in such a case.
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If the frequency graph is shown as grey line the EQ is
disabled. There are two ways to change this state:
¾ Push key EQ again to change to the page EQ Enable /
Presets, see below.
¾ Push key I/O, select current channels, Subpage
Parametric EQ, EQ Enable ON or OFF
Pushing the EQ key a second time brings up the EQ Enable / Presets screen. In this screen
the EQ can be switched on and off, and EQ presets can be stored and loaded comfortably.
Use encoder 1 to change between the subpages Analog Input, Main Output 1/2 and Phones
Out 3/4. These subpages have the following entries:
EQ Enable
Default: OFF. Options are ON, OFF, L, R (L and R are only
available with Dual EQ activated).
Preset Select
Load or store up to 22 different EQ settings. The first choice,
Manual, holds the current, unsaved EQ settings. The second
choice, Temp, holds the settings of a loaded and then modified Preset. This scheme lets the user easily change and
compare three different EQ settings: the manual one, the
stored preset and the modified preset, without loosing
changes while listening to a different set of EQ settings.
The presets are independent from and not stored with Setups (see chapter 14.2). EQ Presets
are therefore always available, no matter which Setup has been loaded. The Setup does include the current EQ setting, which on load is written into the memory slot Manual.
Name
Allows to edit the name of the current preset and to edit the
name during the store process. Turn encoder 2 to select a
letter, number or symbol, then press encoder 2 briefly to
enter the next sign. After the last sign the cursor jumps to the
field Store to. The name can consist of up to 14 signs.
Turning encoder 1 gives access to all existing preset names,
so copying and modifying a preset can be done more
quickly.
Changing the name is always stored immediately during
editing, without further confirmation.
Leaving this field the name is automatically adjusted to the right. Adding signs to the front and
rear is possible afterwards. A quick turn to the left brings up space, which is also used to quickly
delete letters. Available signs are:
Space, Aa to Zz, + - / ( ) * ; : . , ! # $ & < > = ' I @, 0 - 9
Save to
Use encoder 2 to select the slot where the current preset should be stored to. To store press
and hold encoder 2 for one second.
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14. SETUP
The key Setup gives access to two top level screens: Options and Load/Store all Settings. Options has the subpages Hardware/Diagnosis, Device Mode, Clock.
14.1 Options
14.1.1 Hardware/Diagnosis
Subpage Hardware/Diagnosis, has the following entries:
SPDIF In
Available settings are: Auto, Coax, Optical. Default: Auto.
SRC (Sample Rate Converter)
Available settings are: Off, AES In, SPDIF In. Note: In case a DoP signal (DSD) is detected,
SRC is automatically switched off.
Optical Out
Available settings are: SPDIF, ADAT. While the input adapts to the received signal automatically, the output needs to be switched manually. In Dig Thru mode with an ADAT signal received, the output is switched to ADAT automatically with all 8 input channels passed through.
Dig. Out Source
Default, Main Out. Copies the signal Main Out 1/2 (including EQ and volume) to the digital outputs AES and SPDIF/ADAT. Useful when connecting active monitors with digital inputs.
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.
Meter Color
Green, Cyan. Default: Green. Changes the color of the meter screens for PCM and DSD mode.
Remap Keys
OFF, ON. Default: OFF. Allows to assign 26 different functions/actions to the four function keys,
configurable via the following four entries:
VOL Key, I/O Key, EQ Key, SETUP Key. Available functions/actions:
Setup 1 to 9, Mono 1/2, Mono 3/4, Mono to L 1/2, Mono to L 3/4, Mute 1/2, Mute 3/4, Mute all,
Loudness 1/2, Loudness 3/4, EQ In 1/2, EQ Out 1/2, EQ Out 3/4, BT Out 1/2, BT Out 3/4,
EQ+B/T+Ld 1/2, EQ+B/T+Ld 3/4, Toggle Ph/Line.
The original function of the key, entering the menu, is still available by pushing the key for half a
second.
LCD Brightness
Adjustable from 20% to 100%. Default is 80%.
LCD Tint Control
Adjustable from -8 (yellow) to 8 (blue). Enables compensation of the display's colour deviation
as well as suiting the user's taste.
Test Results
Please ignore. For internal use only.
SW Version
Shows the current version number and date of the internal DSP software.
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14.1.2 Clock
The subpage Clock has the following entries:
Clock Source
Choices are Auto, INT (Internal, Master), AES, SPDIF.
Sample Rate
Choices are 44.1, 48, 88.2, 96, 176.4, 192, 352.8, 384,
705.6 and 768 kHz. When clocked externally the ADI-2 Pro
will recognize and handle other frequencies as well, for
example 32, 64 and 128 kHz.
When using 352.8 or 384 kHz sample rate the level meter display will show a single channel of
audio sent out from SPDIF, or received in case a signal of 192 kHz sample rate is attached. The
reason is that the ADI-2 Pro includes a special SMUX mode. When run at Octa Speed, the ADI-
2 Pro will split the data of the left analog input channel to the AES/SPDIF output channels left
and right, at half the sample rate – 192 kHz. Using measurement software like HpW Works
(www.hpw-works.com) which supports this mode (2x speed), and any 192 kHz capable RME
audio interface, one can perform analog measurements with 384 kHz sampling rate bandwidth
over SPDIF – of at least one analog channel.
The big advantage compared to a direct USB connection: using SPDIF optical the tested device
is galvanically isolated from the measuring system (interface/computer), a crucial requirement
when probing in the extreme areas that the ADI-2 Pro allows for.
14.1.3 Device Mode
The subpage Device Mode has the following entries:
Basic Mode
Choices are Auto, AD/DA, USB, Preamp, Dig Thru and DAC. See chapter 17.
Dual Phones
OFF, ON. Default: OFF. With Dual Phones ON the phones
output PH 1/2 will be active. Default state is Off, as PH 3/4
is the main phones output and should be used exclusively
unless two phones are to be connected.
If Dual Phones is on and two phones are plugged in, a push
on VOLUME toggles between 1/2, 3/4 and linked volume
control (with the marker over both). When VOLUME is
turned the Dual Volume screen is shown then.
CC-Mode
Choices are Stereo and Multi-channel. The ADI-2 Pro supports two Class Compliant modes: 2
channel I/O, which allows to use sample rates up to 768 kHz even with iOS devices, and 6/8
channel mode to give access to all I/Os simultaneously. In multi-channel mode the sample rate
is limited to 192 kHz. To be able to change the mode USB must be disconnected.
Bal Phones Mode
OFF, ON, Auto. Default: OFF. In Balanced Phones mode output PH 3/4 carries the left channel,
output PH 1/2 the right channel. See chapter 18 for details. When Auto is selected, the balanced phones mode is automatically activated as soon as both Phones outputs detect a connector being plugged in. This feature temporarily deactivates DSD Direct mode if active.
: When active, the rear analog outputs are muted automatically.
Note
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Phones <=> Line
OFF, 1/2, 3/4, 1/2+3/4. Default: OFF. Activates the ability to toggle mute between Phones Out
and rear Line Out. Pushing the VOLUME knob for half a second will then switch between loudspeakers connected to the rear and phones plugged into the front. This function can also be
controlled by one of the four function keys via Remap Function Keys.
Mute v. TRS 1/2
ON, OFF. Default: ON, but grayed out. As soon as a plug is detected in PH 1/2 the rear outputs
1/2 are muted. Note: This function requires Dual Phones to be on to become accessible. With
Mute v. TRS 1/2 ON the channels Phones 1/2 and Mains Out 1/2 have separated settings. Although both outputs alternately play back the same signal, all settings (Settings, EQ, BT) can
be different, and are separately stored in the background.
Mute v. TRS 3/4
ON, OFF. Default: ON. If set to ON a plug detected in PH 3/4 mutes the rear outputs 1/2.
DSD Direct 1/2
OFF, ON. Default: OFF. When activated a DSD playback will use DSD Direct mode over the
rear outputs 1/2. As DSD Direct bypasses all DSP calculations and volume control, the only
way to change the output volume is by setting different reference levels. Therefore in DSD Direct mode Phones outputs 1/2 are disabled.
DSD Filter
When DSD Direct mode is active, high-frequency noise filters reduce out-of-band noise, which
might have negative impact on other equipment. While 50 kHz is optimized for DSD64 and 150
kHz for DSD 128 and 256, the user can freely try both at any DSD rate.
14.2 Load/Store all Settings
This option allows to save the whole state of the unit as Setup in up to 9 different memory slots.
The EQ Presets are not included, they are stored separately and are available for any setup.
The current state of the EQ is also stored. During load of a Setup the EQ is written to the mem-
ory slot Manual.
The page Setups, Load/Store all Settings, has the following entries:
Setup Select
Choices are Load 1-9, Factory (Reset All) and Store 1-9.
Name
Allows to edit the name of the Setup during the store
process. To edit an existing name load the respective Setup
and store it on the same memory slot with edited name. See
EQ - Name for details about the Edit operation.
Start
Press 1s. Pressing and holding encoder 2 for at least one second triggers the action selected
(Load or Store).
Returning to Factory State
In case a total reset is desired: hold encoder 1 and the VOL button pushed while turning on the
unit. This will reset all current settings to factory default. User-stored Setups and EQ presets are
not affected. The same action is performed by loading Factory via Setup Select. Note that the
reset will be incomplete when the unit is connected to USB while performing the reset.
When holding encoder 1, 2 and the VOL button pushed while turning on the unit, user-stored
Setups and EQ presets are still not affected, but their names are reset as well.
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15. Meter Screens
The ADI-2 Pro has four different meter screens: a global level meter that shows all signal levels
of all I/Os simultaneously, an Analyzer showing the audio signal content on the analog inputs
and both analog outputs 1/2 and 3/4, a state overview showing the digital states of AES, SPDIF
and USB, and a dark Volume screen with comprehensive information.
Pushing the small encoder 1 or 2 while any meter screen is active cycles through all meter
screens. To quickly call them up simply press any of the 4 buttons one or two times.
15.1 Global Level Meter
Shows the signal present at all inputs and outputs. The
upper labels refer to inputs Analog, AES and SPDIF, then
outputs Analog 1/2, Analog 3/4, AES and SPDIF.
At sample rates above 192 kHz AES and SPDIF are
grayed out as they are no longer functional.
These are peak level meters with peak hold function,
bandwidth limited to 40 kHz at higher sample rates.
15.2 Analyzer
The Analyzer is one of the main features of the ADI-2 Pro. Thanks to the high-resolution IPS
panel even smallest details are clear to see. Music content analysis is possible even when
viewed from a greater distance.
The Analyzer is based on RME’s famous Spectral Analyzer in DIGICheck. It uses 29 biquad
bandpass filters for high separation between the bands, providing outstanding musical visualization. Using carefully selected attack and release times the display is responsive, but still easy
to read. On top it uses RME’s own Max LR technique to prevent 6 dB higher level display for
monaural signals, and zero display with out–of-phase signals.
The Analyzer operates at any sample rate, and even with
DSD. There are no parameters to change, and the shown
frequency range is always the human audible range, 0 up
to 20 kHz.
To be able to also show DC content the lowest band is not
a band-pass filter, but a low pass, catching the whole
range from 0 Hz up to 20 Hz. With some unusual signals it
therefore can happen that the level shown will be a bit
higher than expected.
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 Pro DSP, even at 768 kHz sample rate.
The most important application using a Spectral Analyzer is the visualization of frequencies and
levels found in music or speech. The Analyzer shows levels and frequencies even at the edge
of the human ear's abilities – or that of the used speakers and headphone. The visual display
helps to train ones ears, makes coarse errors visible, and shows what sometimes might stay
unnoticed. For example many speakers won't let you hear frequencies below 30 Hz. Simply
look on the Analyzer to see what's going on in the underground.
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