Software dbx-II|Disc Compatible Compander

 
   
  DxII Codec is a modern digital equivalent of the traditional dbx-II/Disc system which was one of the outstanding analog audio tape/LP noise reduction systems. The software is capable of decoding/encoding dbx type-II or type-Disc formatted audio in digital domain, with ease, quality and efficiency. Benefiting from the proprietary DSP engine and intuitive GUI, the process can be accomplished real-timely with smooth user interaction.
 
     
 
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Deeper optimal result can be achieved by using the advanced toolkit which was not available on traditional analog hardware, as specified below:

  • The dual-meter visualizes potential risks of dynamic-range overload or underload, with adjustable means for instant correction.

  • The Azimuth and Gap-Loss tools can compensate minor imperfection of analog tape player used for digitizing audio tapes.

  • The Play Trim is another tool for compensating weakened signal on aged pre-recorded tapes.

  • The EQ Converter offers digital translation between 120μs and 70μs IEC tape equalization standards — if such a flexibility is not offered by a given tape player/recorder.

  • The RMS timing slider offers optional flexibility to adjust the compander's tracking speed.

  • The built-in tone generator offers 1kHz 0 dB Reference Level signal for easy calibration.
Most of the fine-tuning tools can work independently of the dbx-II/Disc codec, which can also be applied for refining non-dbx formatted audio.

DxII Codec is a stand-alone GUI app without relying on any other DAW host. It allows the computer to serve as an external(outboard) dbx-II/Disc unit in one of the following four modes:

  • from Audio-In to File (a digitizer/recorder).
  • from File to Audio-Out (a player).
  • from File to File (an off-line processor).
  • from Audio-In to Audio-Out (a through processor, with slight delay).

Currently supported audio formats are: WAV, MP3, FLAC, AIF, AAC and M4A, up to 96k/24bit.

The software comes with embedded user manual on each major functions.

Please note that this software is suited for the consumer grade dbx type-II or type-Disc, which is not compatible with the professional grade dbx type-I.

 
     
  Audio Demo #1 (Jazz)
Audio Demo #2 (Vocal)
Audio Demo #3 (Electronica)
Audio Demo #4 (Symphony)
Audio Demo #5 (Drum & Beat)
 
     
   
     
     
 

Software vs. Hardware?

 
 

It depends on which domain the audio is to be processed — analog(A) or digital(D)? Apparently, traditional hardware is good for A2A, the new software is better for D2D, and either are ok for A2D or D2A. But there is always more details...

The outstanding noise reduction of dbx-II/Disc system is based on so-called "linear-decibel companding", which was a rather high challenge for analog hardware to precisely implement because "linear-decibel" is essentially logarithm/exponent in practical form. Transistors have to operate in nonlinear region to obtain the desirable logarithmic-/exponential-like behavior, which is a rather narrow, unstable and individually different region, even with dedicated IC chip. Therefore, an analog dbx-II/Disc hardware unit normally requires fine compensations, adjustments and maintenance with pro equipments and experiences. The factory calibration may drift over long time, thus, the original design spec of 100dB dynamic range with < 0.5% THD may not be always guaranteed.

In contrast, DSP (Digital Signal Processor including computer) is particularly good at implementing "linear-f(x)" type of audio companders where f(x) can be any compression/expansion formula, including the special logarithm/exponent used by dbx NR. When customized for reproducing dbx-II/Disc system in digital domain, the algorithm can achieve higher precision and lower distortion than analog hardware without needing compensations, adjustments and regular maintenance, but with gifted digital advantages such as zero new noise, mathematical accuracy, wider dynamic range and much lower cost. It will consistently stay in known working condition. Unlike typical analog dbx-II/Disc hardware which had fixed tolerance co-working with tape/player/recorder, this software is able to collaborate with imperfect partners by providing compensations in azimuth/gap-loss/play-trim/EQ for better overall performance.

However, the software is not made as an upgrade of the original analog dbx-II/Disc system,instead,being as closer as possible. It is designed with full respect to the original system's topology with the same 2:1 pre-emphasized compression and the same 1:2 de-emphasized expansion controlled by true RMS level detector with the same capacitive timing characteristic, even not attempted to "fix" the inherent side-effects such as "breathing" and intermodulation. The software is also not designed for and not fully capable of replacing analog hardware if domain culture matters (the analog vs. digital debate). It is just a new digital alternative that might be needed by those who are transferring audio across the digital/analog border, such as digitizing legacy tapes (A2D) or recording new tapes from bit stream (D2A). In an analog chain (A2A), if a dbx-II/Disc analog hardware is temporarily missing or degraded, the software can serve as a similar role but with double D/A A/D conversion loss. And finally in dealing with pure digital case (D2D), the software will make impossible possible.

 
     
   
   
     
   
   
     
 

Audio Demo #1 (Jazz)
Audio Demo #2 (Vocal)
Audio Demo #3 (Electronica)
Audio Demo #4 (Symphony)
Audio Demo #5 (Drum & Beat)

dbx-II and dbx-Disc are the tape noise reduction systems developed by dbx Inc..

 
     
 
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  Contact: anaxwaves@gmail.com