RME Audio ADI-96 PRO User manual

User's Guide
Constant Double Speed
Analog Processing
Digital Processing
Hi-Precision
24 Bit / 96 kHz Stereo
DSP based Analog / Digital-Converter
CDS
®

2User's Guide ADI-96 PRO © RME
Contents
1Introduction............................................................ 3
2Supplied Contents ................................................. 3
3Brief Description and Characteristics................... 3
4Technical Specifications
4.1 Analog Specs...................................................... 4
4.2 Digital Specs....................................................... 4
5First Usage -Quick Start........................................ 5
6Operation and DSP Functions............................... 6
7General DSP Functions
7.1 Input.................................................................... 7
7.2 Output................................................................. 8
7.3 Setup .................................................................. 9
7.4 Boot other Function............................................10
7.5 Information.........................................................11
7.6 Correlator...........................................................12
8Serial Interface ......................................................13
9DSP Software Dual Mono A/D
9.1 Brief Description and Characteristics..................14
9.2 Low Cut..............................................................15
9.3 Delay..................................................................16
9.4 Expander............................................................17
9.5 De-esser.............................................................18
9.6 Non Linear Compressor......................................19
9.7 Auto Level Control..............................................20
9.8 Look Ahead........................................................21
9.8.1 Expander......................................................21
9.8.2 Auto Level Control........................................22
9.9 Remote Control..................................................23
9.10 Table of Parameters (Presets)............................24
10 DSP Software Stereo A/D
10.1 Brief Description and Characteristics..................26
10.2 Remote Control..................................................26
10.3 Table of Parameters (Presets)............................27
11 DSP-Software Audio Analyser
11.1 Brief Description and Characteristics..................28
11.2 Keyboard Operation............................................28
11.3 Software Audio Analyser.....................................29
11.4 Settings Spectrum Analyser................................30
11.5 Notes on Operation.............................................31
12 Controls and Connectors .....................................32
13 Warranty ................................................................32
14 Addendum.............................................................32
Copyright RME, Matthias Carstens, 12/02. Version 1.5
All entries in this User´s Guide have been thoroughly checked, however no guarantee for correctness can be given. RME
cannot be held responsible for any misleading or incorrect information provided throughout this manual. Lending or copying
any part or the complete manual or its contents as well as the software belonging to it is only possible with the written per-
mission from RME. RME reserves the right to change specifications at any time without notice.
Trademarks
All trademarks or registered trademarks belong to their respective owners.

User's Guide ADI-96 PRO © RME
3
1. Introduction
Congratulations on your purchase of a ADI-96 PRO. This hi-quality analog to digital con-
verter uses the unique Constant Double Speed technology to precisely convert analog audio
data into different digital audio formats. Newest circuit technology combined with modern inte-
grated circuits resulted in a unique and outstanding device, meeting highest quality standards.
The ADI-96 PRO will excite you even after many years of operation.
2. Supplied Contents
Please ensure that all the following parts are included in ADI-96 PRO's packaging box:
•ADI-96 PRO
•Manual
•Power cord
•Serial cable 9-pin D-type
•RME Driver CD including Windows and BeOS software Remote Control
3. Brief Description and Characteristics
The ADI-96 PRO is a 2-channel analog to digital converter in a 19" rackmount enclosure
of 1 U height. Newest 24 bit converters using 64 times oversampling result in 115 dBA dynamic
ratio. This value is not only printed in the brochure, thanks to our Low Jitter Design it is avail-
able with every sold unit.
The servo balanced line inputs are fitted with both XLR and 1/4" TRS jacks separately. The
signal path from the jacks to the ADC is totally balanced. A super low noise amplifier stage
provides 20 dB adjustable gain, set by two hi-precision potentiometers on the front panel. This
brings a perfect adaptation to the most used levels -10 dBV and +4 dBu for each channel sepa-
rately.
The discrete low noise and low distortion microphone preamp works totally independent from
the line circuits. A high quality relais connects the output of the line and mic electronics directly
to the AD-converter. The Mic XLR jacks also provide +48 V of phantom power for condenser
microphones.
The clearly structured front panel design ensures an easy start when working with the device
for the first time. The Peak Level Meter is visualized by a hi-precision LED chain with reliable
Over detection. The AD-converter is able to sample at 32, 44.1, 48, 64, 88.2 and 96 kHz. The
digital output is available at SPDIF (coaxial and optical) and AES/EBU (XLR) connectors.
Thanks to the unique Constant Double Speed technology the crystal clear sound of 96 kHz
sample rate is preserved even when using common sample rates below 64 kHz, as the ADI-
96 PRO samples and calculates in double speed. RME's exclusive Analog Processing
brings typical analog behaviour and sound to the digital domain. When using Look Ahead our
Digital Processing technology minimizes changes in sound even with heavy processing.
The DSP adds phase shift, low cut and mid/side processing in pure digital 48 bit quality. Proc-
essing all data in the DSP avoids all unwanted effects typical for analog circuitry, like additional
noise, distortions, changes in frequency response and deviations between both channels. Cal-
culating Phase, Low Cut, Expander, De-esser, M/S-Processing and Compressor by a 48 bit/96
kHz DSP results in a previously unreached sound quality.

4User's Guide ADI-96 PRO © RME
4. Technical Specifications
•Power supply: Internal, 110 / 230 V AC, 30 Watts
•Dimensions 483 x 44 x 205 mm
•Weight: 2 kg
4.1 Analog Specs
•Resolution AD: 24 bit
•Dynamic ratio: > 115 dBA
•THD+N: > 100 dB, < 0.001 %
•Maximum input level AD: +22 dBu
•Minimum Line input level for 0 dBFS: +2 dBu
•Minimum Mic input level for 0 dBFS: -50 dBu
•Frequency response AD, -0.1 dB: 10 Hz -21 kHz (sf 44.1 kHz)
•Frequency response AD, -0.5 dB: 5 Hz –44.8 kHz (sf 96 kHz)
•Input Line: XLR, 1/4" TRS, servo balanced
•Input impedance Line: 10 kOhm
•Input Mic: XLR, servo balanced, +48 V phantom power switchable
•Input impedance Mic: 2 kOhm
4.2 Digital Specs
•Super Low Jitter Design: < 3 ns in word clock PLL operation
•Output voltage: coaxial 0.5 Vpp, XLR 5 Vpp
•Output format: Consumer with/without copyright, Professional
•Supported sample rates: 32 kHz, 44.1 kHz, 48 kHz, 64 kHz, 88.2 kHz, 96 kHz
•Supported sample rates by word clock: 25 kHz -105 kHz
•Internal resolution: 48 bit
•Resolution on digital output: 8, 16, 20, 24 bit
•Dither: 0 / 0.5 / 1 LSB triangular switchable
•Dither method: DC-offset free adding and rounding
•Output optical (TOSLINK), coaxial, XLR
•Format output SPDIF and AES/EBU (Consumer/Professional)
•Word clock input or output switchable
•Serial RS-232 interface

User's Guide ADI-96 PRO © RME
5
5. First Usage -Quick Start
Connect your analog signal source to the ADI-96 PRO's XLR or TRS input jacks. First
adjust the knobs fully counterclockwise and try to achieve an optimum input level by adjusting
the source itself. Fine adjusting the input level can easily be done by watching the Peak Level
Meter while turning the knobs. The best input level is present when all LEDs except the Over
LEDs are lit at the loudest parts of the signal. When there is no level indication at all, check the
actual input state (Mic/Line) in menu INP for left and right channel.
The analog line inputs of the ADI-96 PRO can be used with +4 dBu and -10 dBV signals.
The ADI provides (stereo) TRS and XLR jacks. Both are internally connected, so not opera-
tional at the same time. The electronic input stage is built in a servo balanced design which
handles monaural and stereo jacks correctly. When used unbalanced it automatically corrects
the gain by 6 dB.
When using unbalanced cables with XLR jacks we recommend to short pin 3 of the cable's
jack to pin 1 (ground). Otherwise noise may occur, caused by the unconnected negative
input of the ADI-96 PRO's input jack.
The Mic XLR jacks also provide +48 V of phantom power for condenser microphones (menu
INP, Mic. Phantom Powered, separately for left and right channel).
When switched on for the first time the DSP software Dual Mono A/D is started. To change to
another DSP software see chapter 7.4 'Boot other function'.
It is more than likely that when using the device for the first time some additional settings in the
digital section have to be changed. The device is shipped with 16 presets, of which preset 1
and 2 are highly compatible to common equipment. Please choose correct sample frequency
and format (Professional, Consumer) in the menu OUT, according to the capabilities of the
device connected to the ADI-96 PRO's output.
Coaxial, optical and XLR jack of the digital output always carry the same signal. A connec-
tion to professional devices with AES/EBU inputs requires the channel status Professional.
With this setting consumer DATs connected in parallel will not start to record, as they require
the format 'Consumer'.
Transferring digital data into a PCI bus equipped computer is best done using RME's digital
interface cards of the DIGI96®and Hammerfall®series. These hi-quality cards come with driv-
ers for all popular operating systems. They have a world wide reputation as ultimate solution for
master and multitrack tasks.
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6User's Guide ADI-96 PRO © RME
6. Operation and DSP Functions
The ADI-96 PRO's user interface is easy to understand thanks to its clearly structured
front panel design. The big and bright 2 x 20 character LC-display plus a simple and straight
cursor controlled menu structure will probably make you never look into this manual. Because
of the numerous functions found in the ADI and its software, we strongly encourage you to
study this manual.
Let's start with a short introduction into the ADI-96 PRO's user interface philosophy.
After power-on and automatic calibration the Info window will come up and show the currently
loaded DSP software. The device remembers all settings even without saving them. To be sure
a certain setup is being used unaltered, you should first reload it using Recall (see 6.9 Setup).
Press Enter to bring up the Overview window, which displays all configurations and the avail-
able DSP functions. Each function is represented by three letters, and is the highest menu of
several submenus.
On this level each function can be activated and de-activated (Bypass) using the +/-keys.
That's why they are also labeled ON/OFF. Below this row of functions two lines out of thin lines,
fat lines and bars can be seen. These two lines represent one channel each. The state of each
function is shown by a thin line (off) and a fat line (on). The screenshot below shows all func-
tions activated except LOC (Low Cut). A global bypass, useful for comparing the sound with
and without DSP functions can be set by pressing the additional key Bypass DSP.
To avoid pan shifts between left and right channel the control paths (sidechains) of some func-
tions can be linked. As shown in the above screenshot, Link is activated for the function EXP
(Expander), because both channel rows are no longer separated, but combined by bars. The
functions OUTPUT and SETUP can not be deactivated nor set up separately, so no lines are
shown at all. INPUT can't be deactivated, but in the stereo version of the DSP software the
channels are linked.
To enter a sub menu first use the arrow keys to move the cursor (shown as a blinking of the
corresponding three letters) in the desired direction. The Overview window will begin to scroll
because not all functions can be displayed simultaneously. An arrow will show up at the left and
right border of the display, indicating that some more functions are available (see picture
above). The submenus are accessed by pressing Enter, a second press on Enter jumps back to
the Overview window.
The button Meter Mode allows to switch the Peak Level Meter and the Correlator before (Input)
or behind (Output) the DSP. This allows to check changes in level and phase caused by the
activated functions without the need to switch the DSP in bypass mode.
Scrolling through the values with the +/-keys becomes accelerated when pressing the buttons
for a longer time. A jump to the highest or lowest possible value is done by first pressing one,
then the other key additional.
On the following pages you'll find detailed informations to all functions currently available in the
factory shipped DSP software Dual Mono A/D.

User's Guide ADI-96 PRO © RME
7
7. General DSP Functions
7.1 Input
Function
Choice of input (Mic, Mic phantom powered, Line) per channel, invert phase (180°) per chan-
nel, activation of M/S processing.
Application
The setting Mic. Phantom Powered will apply 48 V DC to the XLR Mic jacks, so an operation
with condenser microphones is possible without the need of an external supply.
Inverting the phase allows to correct mics having a wrong polarity, or enables special effects in
'out of phase' technique.
The mid/side principle is a special positioning technique for microphones, which results in a mid
signal on one channel and a side signal on the other channel. The M/S processing transforms
these signals in a normal left/right stereo signal. Thus the mid/side signal is M/S decoded.
Settings
Place the cursor in the Overview window on INP and press Enter.
Menu
Options
Choice of Mic or Line input, activation and de-activation of phase invert and M/S processing.
Typical Settings
The mid/side processing automatically operates as encoder or decoder, depending on the sig-
nal feed. When processing a usual stereo signal all monaural informations will be shifted into
the left channel, all stereo information into the right channel. Thus the stereo signal is M/S en-
coded. This gives some very interesting possibilities of manipulating the stereo base and gen-
erating stereo effects, as it is possible to process the stereo information with all the functions
found in the ADI-96 PRO, like LOC, EXP, ALC and Delay. To avoid any processing of the
left channel (the monaural information) simply set all parameters to their lowest value (so the
functions won't change the audio data).
After this processing the signal must again run through the M/S processor to convert the
mid/side signal back to a normal stereo signal. Many software audio editors (like Steinberg's
WaveLab) include such an M/S function. That way, the second processing can be done in the
digital domain, for example on a Windows PC.

8User's Guide ADI-96 PRO © RME
7.2 Output
Function
Configuration of the signal at the digital output: Sample frequency, word length, Dither, word
clock and Channel Status.
Application
Allows to set the parameters of the digitization, and allows to make the ADI-96 PRO fully
compatible to all devices attached to its digital output.
Settings
Place the cursor in the Overview window on OUT and press Enter.
Menu
Options
Adjustable are:
•Sample rate 32 kHz, 44.1 kHz, 48 kHz, word clock < 64 kHz, 64 kHz, 88.2 kHz, 96 kHz,
word clock > 48 kHz
•Audio word length 8 bit, 16 bit, 20 bit, 24 bit
•Dither OFF, 0.5 LSB, 1.0 LSB
•Word clock output OFF/ON
•Channel Status Professional, Consumer with copyright, Consumer without copyright
Typical Settings
In case the ADI-96 PRO shall be clocked from an external 44.1 kHz or 48 kHz word clock
signal choose the setting Word Clock < 64 kHz.
Consumer devices like DAT and MiniDisc won't accept digital signals in Professional format at
their SPDIF jacks. For this setup please choose Consumer without Copyright.
The choice of the word length determines the maximum resolution of the audio data at the
ADI-96 PRO's output. At less than 24, for example when transferring on a 16 bit DAT, we
recommend to choose Audio Wordlength 16 Bit, and also to activate the Dither function, to
avoid distortions on very low level signals.
What Dither does can be easily shown at the setting Audio Wordlength 8 Bit, which results in a
dynamic of only 48 dB at the output. Low level signals will suffer from high distortion. After
activation of Dither 1.0 LSB a special noise signal is added which removes any audible distor-
tion.
When activating Word Clock Output ON the device will provide a word clock signal of the cur-
rent internal sample rate, available at the BNC jack on the rear of the device.

User's Guide ADI-96 PRO © RME
9
7.3 Setup
Function
Configuration of Peak Level Meter, LC-display and preset memory.
Application
Allows to change the display behaviour of all elements on the front panel, and to store and
recall different configurations.
Dependent on the used DSP software the ADI-96 PRO includes up to 16 user presets. All
settings except the ones found in the Setup menu will be stored (the setting of contrast and
Level Meter is global). Each preset can be stored under an individual name. The desired num-
ber or letter is available by pressing the +/-keys, the arrow keys will move the cursor to the
next position.
Copying one preset to another place can be done by first recalling the desired preset, than
store it to the other location. A security function prevents overwriting data by mistake.
Settings
Place the cursor in the Overview window on SET and press Enter.
Menu
Options
Adjustable are:
•Level Meter Peak Hold 0.1 s up to 9.9 s
•Level Meter Release 1 dB/s up to 100 dB/s
•LC-Display Contrast 1 up to 10
•Save Setup 1 up to 16
•Recall Setup 1 up to 16
•Boot other function
Typical Settings
Most people will adjust the hold time of the peak level to around 1 second. A level meter with
fast reaction is also desired by most people, for this the Level Meter Release should be set to
the highest value of 100 dB/s.
Informations to the menu entry Boot other function can be found in the next chapter.

10 User's Guide ADI-96 PRO © RME
7.4 Boot other Function
Function
Starts the Bootloader.
Application
The Bootloader is nearly the same as the BIOS of a PC, it is the ADI's operating system at
lowest level. Its main task is to load the DSP (audio) software after switching on the device. But
there are some more functions it provides:
•Loading other DSP (audio) software from the internal memory
•Loading other DSP (audio) software from the serial interface
•Performing several hardware tests
Settings
Place the cursor in the Overview window on SET and press Enter, then use the right arrow key
to scroll to Boot other function, then press Enter.
Menu
Options
Boot DSP-Software allows to choose from several DSP programs, stored in the ADI-96
PRO. Currently you'll find the DSP software Dual Mono A/D, an identical but easier to use
version called Stereo A/D, and an Audio Analyser providing realtime 1/3 oct analysis. Updates
will be available on our website for free and can easily be uploaded into the ADI-96 PRO
using Load Flash from PC (see chapter 8. Serial Interface).
Reload Presets allows to reload all factory setups of the corresponding DSP software. This will
erase all user settings.
The Test Procedures include the following tests:
•Calculate Checksum Flash (checks the Flash memory)
•Samplerate Generator (checks the function of the Clock PLL)
•Keyboard (allows to test all keys on the front panel)
•Display (lights up all LEDs and all signs of the LC-display)
•RAM Pattern Test (checks the RAM memory used by the DSP)
Typical Settings
None

User's Guide ADI-96 PRO © RME
11
7.5 Information
Function
Gives an overview on the current configuration. Shows the DSP software's version and name.
Application
The Information window gives a useful overview on which input is being used (Mic or Line), the
active clock source (internal or word clock), the current sample frequency (shown in kHz) and
word length. The ADI-96 PRO displays the Info window automatically after 100 seconds,
in case no cursor key was pressed during this time.
In word clock operation the Info window shows the actual frequency of the word clock signal
feed, at missing word clock WCK error is shown.
The second Info window is automatically shown after switching on the device and shows name
and version of the currently loaded DSP software.
Settings
Place the cursor in the Overview window on INF and press Enter.
Menu
Options
None
Typical Settings
None

12 User's Guide ADI-96 PRO © RME
7.6 Correlator
Function
Shows the correlation between left and right channel. Simply said: measures the phase be-
tween left and right.
Application
Checking mono-compatibility, checking polarity of microphones, detecting sound problems due
to delay and phase settings.
Settings
The Correlator has no settings, its behaviour depends on the release time set for the Peak
Level Meter. Place the cursor in the Overview window on SET and press Enter.
Menu
Options
Level Meter Release 1 dB/s up to 100 dB/s.
Typical Settings
As with the Level Meter a faster setting (100 dB/s) is preferred by most users.
This function calculates the (mathematical) correlation between left and right channel. In sim-
pler terms, the correlation gives an indication of the mono compatibility of the audio signal.
The value 1 measured with a sine corresponds to identical phase on both channels. In this case
summing the channels (mono mode, reduced channel separation or a distant listening position)
won't result in any loss of sound, the channels are 'in phase'. This is different with lower correla-
tion values. In practice values between 1 and 0 indicate problem-free material.
0 corresponds to a phase deviation of 90° between left and right channel. An indication cen-
tered around 0 or slightly shifted into the red range (0 to -1) indicates material which might
cause problems when converted to mono, or which might already suffer from frequency cancel-
lations.
-1 means out of phase (180°). In this case a summing of the channels may result in a loss of
sound, a stereo signal will completely erase itself when processed monaural.
The correlation meter can be used not only for the evaluation of existing material, but also for
testing positions of microphones or their polarity before starting a recording.

User's Guide ADI-96 PRO © RME
13
8. Serial Interface
Function
Enables connection to and data transfer to and from any Windows PC.
Application
Depending on the used software the ADI-96 PRO can be completely remote controlled,
setups can be loaded/stored/edited, and new DSP software can be loaded into the device.
Settings
To load new DSP software: Place the cursor in the Overview window on SET and press Enter,
then use the right arrow key to scroll to Boot other function, then press Enter, then scroll right to
Load flash from PC.
Menu
Loading new DSP Software
Connect the COM-port of your Windows PC and the RS-232 interface of the ADI-96 PRO
using the supplied D-type 9-pin cable. Start the Windows software adsp_xx.exe and choose
the currently used port of the PC (COM1/COM2). Now the software waits for the ADI-96
PRO to start the transmission. Activate Load Flash from PC by pressing Enter at the ADI,
the data transfer begins and ends automatically.
To activate the new software the ADI-96 PRO has to reboot with it. Change to the
menu 'Boot DSP-Software' and use the +/-keys to choose the desired DSP software.
Storing / Loading / Editing of Setups
These functions are available through the Windows software Remote Control, see chapter 9.9
Remote Control.
Reset
When tranferring new DSP software over the serial interface into the ADI there is a slight
chance the transmission might fail. In this case the ADI might be unable to boot and will hang
when trying to load the incorrectly transferred software. To correct this, a new transfer or at
least a reload of any internal software must be possible. This requires the Bootloader to be
started. To ensure this the Bootloader is not only available through a menu of the DSP soft-
ware, but also when switching on the device.
To activate the Bootloader press the Enter key while switching on the ADI-96 PRO.
The Bootloader now allows to load internal software or a transfer via 'Load flash from PC'.
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14 User's Guide ADI-96 PRO © RME
9. DSP Software Dual Mono A/D
9.1 Brief Description and Characteristics
The DSP software Dual Mono A/D adds some outstanding audio functions to the ADI-96
PRO, required for a hi-class and convenient analog to digital conversion. Combined with the
general functions of the ADI-96 PRO result in a versatile, supersonic Microphone/Line
Audio Processor, replacing several external devices.
Dual Mono A/D includes the following functions:
Low Cut
High pass for reduction of low frequency noise
Delay
Delay of the audio signal per channel from 0 ms up to 170 ms, activation of Look Ahead
Expander
Dynamic level reduction to reduce noise in low level parts or between tracks
De-esser
Removes disturbing sibilants on speech and vocal recordings
Non Linear Compressor
Non linear compressor or Soft-Limiter. Similar to the effect known as tape saturation
Auto Level Control
Operates as Auto Leveler, Auto Gain and digital Compressor
Windows Software Remote Control
Complete remote control of the ADI-96 PRO through a PC. Visualisation of all exter-
nal/internal levels. Storing/loading/editing of Setups
Look Ahead
RME's exclusive Analog Processing brings typical analog behaviour and sound to the digital
domain. Our Digital Processing technology with Look Ahead minimizes changes in sound when
using Expander and Auto Level Control.

User's Guide ADI-96 PRO © RME
15
9.2 Low Cut
Function
Hi-pass with adjustable corner frequency between 2 Hz and 250 Hz at 12 dB/oct.
Application
Removes low frequency noise in microphone recordings, rumble and flutter when converting
older analog material, hum in speech recordings.
Settings
In the Overview window place the cursor on LOC and press Enter.
Menu
Options
The begin of the bass suppression (corner frequency) is adjustable in each channel from 2 Hz
to 250 Hz.
Typical Settings
In mixing desks values around 120 Hz are usual. As the filter has a smooth roll-off 50 Hz hum
will be noticeably reduced with this setting, but the harmonics at 100 Hz and above won't.
That's why the filter can work up to 250 Hz. In extreme situations such a setting is able to res-
cue a speech recording.
Noise and the low frequency pops of microphones do not require such an extreme cutoff at
lower frequencies. Recommended values are 50 to 80 Hz.
Low frequency rumble as of turntables (or other signals which lead to slowly pumping loud-
speakers) are already suppressed with a setting of 30 Hz, which results in no audible bass re-
duction. When mastering often all frequencies below 30 Hz are lowered. Several electronic
sound sources, especially Synthesizers and Keyboards, generate high amounts of inaudible low
frequency junk, which stresses power amps and loudspeakers, but has no effect on the feelable
and audible bass bottom.

16 User's Guide ADI-96 PRO © RME
9.3 Delay
Function
Delay of the audio signal per channel from 0 ms up to 170 ms, activation of Look Ahead.
Application
Allows to correct the time alignment of left and right channel, for example when doing micro-
phone recordings. Allows to correct the time alignment of PA systems. Allows to produce stereo
effects by delaying one channel. Activates the Look Ahead mode for optimized sound quality
with Expander and Auto Level Control.
Settings
Place the cursor in the Overview window on DLY and press Enter.
Menu
Options
The delay of the audio signal can be set from 0 ms up to 170 ms per channel.
Typical Settings
When doing a stereo microphone recording where the mics don't have an identical distance to
the sound source the Delay function allows to delay one channel so the signal at the digital
output of the ADI-96 PRO is time aligned again.
The speed of sound is about 340 m/s. A difference of one meter in the above situation already
requires a correction by 3 ms! The Correlation meter (see chapter 7.6 Correlator) is a valuable
help in fine tuning the neccessary correction, but for the coarse values you'll also need a
calculator and a foot rule.
Other time alignment problems may require to delay both channels in an identical manner. The
maximum setting of 170 ms enables a simultaneous output of loudspeakers in a distance of 56
meters together with loudspeakers placed near the listening person.
The human ear will detect a signal as monaural when amplitude (loudness) and time related
output of left and right channel are identical. When one channel is delayed up to 10 ms the
signal which formerly seemed to come out of the middle will fall apart into two signals, indi-
vidually sent by left and right channel. This may be used as some kind of simple stereo effect
generator, but a very good generator needs some more tricks like modulation on the delay,
short reverb and changes in the frequency response, which are not available here.
One way to achieve a very ecfficient stereo manipulation is to use the M/S processing (encod-
ing), as the stereo informations on the right channel can be single processed by Compressor
and Delay within the ADI. See chapter 7.1.
Expander and ALC will enter the Look Ahead mode in case the Delay is activated and the delay
time is at least 0.1 ms. Informations on how to set up the Delay for best performance with Ex-
pander and Auto Level Control can be found in chapter 9.8.

User's Guide ADI-96 PRO © RME
17
9.4 Expander
Function
Level dependent level reduction, each channel with adjustable threshold (-30 dB to -110 dB),
release (0.1 s to 25.5 s), ratio (1.2 to 5.0) and attack time (Fast 1 ms or Slow 25 ms).
Application
Allows broadband suppression of noise, removal of noise and hum in low level parts or be-
tween tracks, and de-compression of highly compressed material.
Settings
Place the cursor in the Overview window on EXP and press Enter.
Menu
Options
Adjustable are:
•Threshold -30 dB to -110 dB. When the overall level is lower than this value the Expander
begins to reduce the level.
•Ratio 1.2 to 5.0. Defines the ratio between original and reduced level.
•Release 0.1 s to 25.5 s. Defines the time needed to reach 20 dB level reduction after the
last overall level exceeded the threshold value.
•Attack Fast (1 ms) or Slow (25 ms).
•Link Left/Right. Avoids pan shifts by combined controlling of both channels.
Typical Settings
As opposed to a Noisegate an Expander does not switch off audio when the Threshold is no
longer reached. Instead the level is lowered smoothly according to the chosen ratio. A ratio of
1.2:1 equals nearly no change, because a change in input level of 10 dB leads to a 12 dB chan-
ge in output level (only 2 dB difference). Typical Ratio values are 2 to 3 at a Release of 2 s.
That way, music can be faded in and out without heavy side effects. Noise between tracks can
be reduced easily.
The Threshold of the Expander has a strong relationship with the audio material and the noise
in it. LPs often require a Threshold of -30 dB (plus Attack Slow, see chapter 9.8), while re-
cordings from hi-quality sources often only need values around -75 dB. At values of -100 dB
the dynamic range of the ADI-96 PRO can be increased.
With more extreme settings like Ratio 5:1 and Release 0.1 s the Expander operates like a Noi-
segate. With these settings it is possible for example to isolate percussive instruments from
environmental noise.
The settings Ratio 1.5:1 and a Release of around 0.5 s allows to de-compress signals which
were too strong compressed before. This will result in a more natural, open sound, but the origi-
nal can't be recovered completely.

18 User's Guide ADI-96 PRO © RME
9.5 De-esser
Function
Selective dynamic level limiter with automated relative level control. Removes disturbing sibi-
lants on speech and vocal recordings, or other level peaks present in its operating range.
Application
In general there are several methods used to reduce sibilants:
Fixed bandpass -an Equalizer with fixed cut in the sibilant frequency area. Results in a con-
stant muffled sound. Not useable on masters.
Dynamic lowpass -cuts all high frequencies according to the level found in the sibilant area.
Requires a threshold setting adopted to the actual signal. Not useable on masters.
Dynamic bandpass -Requires a threshold setting adopted to the actual signal.
The method used in the ADI-96 PRO is a dynamic bandpass with all its advantages, but
does no longer need a threshold to be set according to the actual signal. Using an automated
relative function the overall level is compared to the level in the sibilant area, the threshold is
automatically set to always achieve the same sound. The level of the actual signal doesn't mat-
ter anymore.
Settings
Place the cursor in the Overview window on DES and press Enter.
Menu
Options
Adjustable are:
•Key Listen. Allows to monitor the filtered signal. Helps to find the best filter setting for an
ideal signal reduction within the desired frequency area
•Frequency 0.7 kHz up to 20 kHz. Center frequency of the bandpass
•Q 0.2 up to 10. Quality factor, defines the width of the bandpass (width of controlled area)
•Ratio 0 dB up to -50 dB. Relative level reduction of the bandpass area
Typical Settings
Sibilants will show up between 4 kHz and 8 kHz. Due to the nearly inaudible operation of the
ADI-96 PRO the Q parameter can be set to a lower value (thus resulting in a larger de-
essed area), for example 1. The Ratio setting depends on the desired sound and the previously
applied equalizing. In an already mastered material a Ratio of up to -10 dB is possible without
getting noticeable reductions. Pure speech and vocals can be processed at settings of up to -30
dB. Too high a value will result in a constant treble reduction, although the De-esser is still
working as a dynamic filter.
Because of the automated relative level control the setting once found to meet your personal
taste does not need any further changes even when the input level is totally different.

User's Guide ADI-96 PRO © RME
19
9.6 Non Linear Compressor
Function
Non linear compressor. The input signal is processed with a special amplitude function which
softly cuts the highest level peaks. The resulting third order harmonics are widely masked by
the original signal, thus inaudible in most situations. Similar to the effect known as tape satura-
tion.
Application
Allows to provide additional headroom of up to 5 dB without audible clipping (clipping: brickwall
limiting leading to high distortion). Allows to increase the loudness without increasing the maxi-
mum peak level (similar to the effect known as Maximizer).
Settings
Place the cursor in the Overview window on NLC and press Enter.
Menu
Options
Adjustment of the desired gain in loudness (level) from 1 dB to 5 dB.
Typical Settings
As long as not very delicate signals from solo instruments or complete mixes are processed the
Non Linear Compressor is a marvellous tool for every recording and may be always activated
at Gain 5 dB. It helps especially when doing live acoustical recordings to gain additional head-
room and operates like a compressor without attack or release time, thus operating virtually
inaudibly.
The NLC may be used to achieve increased loudness without any pumping when processing
material already normalized near 0 dBFS. When used in combination with the ALC and fast
settings the increase in loudness can be more than extreme, but will also result in compacted
death material without any dynamic left.

20 User's Guide ADI-96 PRO © RME
9.7 Auto Level Control
Function
Automatic level control with adjustable gain range and adjustable operating speed per channel.
Application
Serves as automatic level control for long term recordings, raises the volume to avoid low level
recordings. Useable as Leveler or -at faster settings -digital Compressor.
Settings
Place the cursor in the Overview window on ALC and press Enter.
Menu
Options
Adjustable are:
•Maximum Gain 0 up to 24 dB. Defines the maximum gain in level.
•Headroom 1 up to 12 dB. Ratio between average level and maximum (0 dBFS) level.
•Rise 0.1 s up to 25.5 s. Time needed for a 20 dB gain change.
•Link Left/Right. Avoids pan shifts by combined controlling of both channels.
Typical Settings
A usual compressor reduces the dynamic range above a defined level (Threshold) using a de-
fined Ratio (for example 3:1). The ALC raises all signals beneath the maximum level (0 dBFS)
until they reach 0 dBFS minus Headroom.The maximum level gain is 24 dB, so a signal at -30
dBFS will be raised to a level of -6 dBFS. Because of the finite reaction time the average am-
plification has to be limited by the parameter Headroom to a value beneath 0 dBFS. In dynamic
material Headroom determines the ratio between peaks (maximum 0 dBFS) and average level.
When doing acoustic recordings the ALC can improve the average level significantly, recom-
mended settings are up to 15 dB Gain. Recordings from uncritical sound sources (like speech)
can be processed up to 24 dB, so the ALC serves as a real automatic level control. The Rise
time should be longer than 10 s to avoid unwanted pumping. The ALC will change the level
slowly and smoothly in a non-disturbing way.
At very short Rise settings the ALC operates as digital compressor. The parameter Rise then
equals the commonly known Release. Most important is the parameter Headroom. A setting of
1 dB increases the loudness, but will also lead to a 3 ms cutoff of all peaks (Clipping). Because
of the short time this is normally inaudible. In case the ALC shall preserve a more natural
sound settings of more than 3 dB are recommended. From 7 dB up to 12 dB the internal attack
time is doubled to 6 ms, because the higher headroom results in very rare clipping. After acti-
vation of a sufficient delay time (see chapter 6.3 Delay) the ALC works in Look Ahead mode
without any clipping (see chapter 9.8).
The combination of NLC set to Gain 5 dB and ALC set to Headroom 1 dB, Gain 5 dB and Rise
2 s results in an extreme increase of loudness at very little side effects (pumping), similar to the
effect known as Maximizer.