User manual RME ADI96PRO

User's Guide ® CDS ® Constant Double Speed Analog Processing Digital Processing Hi-Precision 24 Bit / 96 kHz Stereo DSP based Analog / Digital-Converter Contents Introduction ................................................................. 3 Supplied Contents....................................................... 3 Brief Description and Characteristics.......................... 3 Technical Specifications ............................................. 4 4.1 Analog Specs ............................................................ 4 4.2 Digital Specs ............................................................. 4 5 First Usage - Quick Start ............................................ 5 6 Operation and DSP Functions .................................... 6 7 General 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 8 Serial Interface.......................................................... 13 9 DSP 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 1 2 3 4 Copyright © RME, Matthias Carstens, 7/99. Version 1.4 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 permission from RME. Changes due to technical reasons will and can happen without the need of notification to anyone. Trademarks All trademarks or registered trademarks belong to their respective owners. 2 User's Guide ADI-96 PRO © RME 1. Introduction Congratulations on your purchase of a ADI-96 PRO. This hi-quality analog to digital converter uses the unique Constant Double Speed technology to precisely convert analog audio data into different digital audio formats. Newest circuit technology combined with modern integrated 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 available 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 separately. The integrated 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 with 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 ADI96 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. Processing 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. Calculating 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. User's Guide ADI-96 PRO © RME 3 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: 5 Hz - 45 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 4 User's Guide ADI-96 PRO © RME 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 LED's except the Over LED's 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 operational 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. G 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 menu OUT according to the capabilities of the device connected to the ADI-96 PRO's output. G Coaxial, optical and XLR jack of the digital output always carry the same signal. A connection to professional devices with AES/EBU inputs requires the channel status Professional. With this setting consumer DAT's 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 in® terface cards of the DIGI96 series. These cards with highest reputation are the ultimate solution for master and multitrack tasks. Drivers are available for Windows 95/98/NT and MacOS, soon for Linux, Unix, Solaris and BeOS. User's Guide ADI-96 PRO © RME 5 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 available 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) by 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 functions activated except LOC (Low Cut). A global bypass, useful for comparing the sound with/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 functions 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. 6 User's Guide ADI-96 PRO © RME 7. General DSP Functions 7.1 Input Function Choice of input (Mic, Mic phantom powered, Line) per channel, invert phase (180°) per channel, 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 signal 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 encoded. This gives some very interesting possibilities of manipulating the stereo base and generating 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. A special DSP software which acts as complete stereo processing application inside the ADI-96 PRO will be available at a later time. User's Guide ADI-96 PRO © RME 7 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 distortion. When activating Word Clock Output ON the device will provide a word clock signal of the current internal sample rate, available at the BNC jack on the rear of the device. 8 User's Guide ADI-96 PRO © RME 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 number 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. User's Guide ADI-96 PRO © RME 9 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 10 User's Guide ADI-96 PRO © RME 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 User's Guide ADI-96 PRO © RME 11 7.6 Correlator Function Shows the correlation between left and right channel. Simply said: measures the phase between 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 simpler 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 correlation 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 centered 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 cancellations. -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. 12 User's Guide ADI-96 PRO © RME 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 actual 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. G 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 software, but also when switching on the device. G 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'. User's Guide ADI-96 PRO © RME 13 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 external/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. 14 User's Guide ADI-96 PRO © RME 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 rescue 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 loudspeakers) are already suppressed with a setting of 30 Hz, which results in no audible bass reduction. 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. User's Guide ADI-96 PRO © RME 15 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 microphone 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, individually 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 (encoding), 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 Expander and Auto Level Control can be found in chapter 9.8. 16 User's Guide ADI-96 PRO © RME 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 between 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 change 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 recordings 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 Noisegate. 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 original can't be recovered completely. User's Guide ADI-96 PRO © RME 17 9.5 De-esser Function Selective dynamic level limiter with automated relative level control. Removes disturbing sibilants 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 constant 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 matter 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 deessed 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. 18 User's Guide ADI-96 PRO © RME 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 saturation. 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 maximum 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 headroom 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. User's Guide ADI-96 PRO © RME 19 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 defined 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 amplification 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, recommended 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 activation 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. 20 User's Guide ADI-96 PRO © RME