dbx SysInfo


A live performance sound's live because of three basic characteristics of music: tonal balance, spatial perspective, and dynamic range.

Correct tonal balance, or flat frequency response, requires uniform reproduction of sound across the audible frequency range.

Spatial perspective is the dimensional quality of music that allows you to recognize that instruments and voices are reaching your ears at different times and from different locations.

The third, dynamic range, is the difference in volume, measured in decibels, between the loudest and quietest passages of a musical selection. From the 120 dB thundering transients of an orchestra or rock group, to the 30 dB subtle nuances of a triangle or flute.

In order for your stereo system to sound more like a live performance, it has to accurately reproduce all three of these basic characteristics of live music.

When dbx entered the high fidelity scene, audio manufacturers had already made a lot of progress in tonal balance and spatial perspective. So dbx began by addressing the problem everyone else was ignoring: dynamic range.



The problem is that conventional records have always been severely limited in dynamic range. Instead of the 90 dB of a live performance, they provide only 50 dB, or 60 dB from the best audiophile discs. Any attempt to record music with greater dynamic range on a vinyl record results in groove excursions simply too extreme for the phonograph stylus to track.

A similar problem exists with tape. Too wide a dynamic range can saturate the tape, causing distortion of the music.

So, audio engineers have been forced to compress dynamic range during recording. They actually squeeze the music, so the louds don't sound as loud as they should, and the softs don't sound as soft. Add to that the problems of record surface noise and tape hiss-which interfere with quiet musical passages - and you can appreciate how dynamic range has suffered in the music recording and reproduction process.

In fact, even with the finest hi-fi equipment and the best conventional records and tapes, you still lose about 1/3 of the dynamic range that was present in the original performances.



The breakthrough came when dbx applied the linear decibel companding process to home audio equipment. Because the process not only reduces noise. It also allows the full dynamic range of the source material to be reproduced.

Their first products were tape noise reduction systems used for taping live music without loosing dynamic range.

Then dbx adapted this process to develop a new family of products which you can use to greatly improve the dynamic range of music from conventional records and tapes as well as radio broadcasts. This new family of products is called dynamic range expanders.

But the major goal still remained; to hear the full dynamic range of a live performance from records in your own home.



Again, linear decibel companding was the answer.

Very simply, dbx went to the source of the problem: the actual cutting of the master disc from which records are eventually made. Instead of arbitrarily compressing or limiting dynamic range as the music signal is transferred from master tape to master disc, dbx precisely compresses the music by a 2 to 1 ratio. The resulting encoded signal fits comfortably within the dynamic range Limitations of vinyl records. Than, when the record is played back through a dbx Disc Decoder, the music signal is expanded in an exact mirror image fashion by a 1 to 2 ratio. This restores the full signal of the music as captured on the master tape.

With dbx Discs, you can hear music with dynamic range equal to that of studio master tapes.

Around 1980, dbx introduced Digital dbx Discs, produced from tapes made by the new digital recording process. The result is the full 90 dB dynamic range of a live performance.

In addition, dbx Discs and Digital dbx Discs virtually eliminate the ticks, pops and surface noise of conventional records. So for the first time, you can listen to the music instead of the record - a major breakthrough in music reproduction.



dbx was attacking the remaining problems in reproducing sound that approaches the realism of a live performance.

dbx Subharmonic Synthesizer can enhance the bass response of your stereo system to include the natural subharmonics of live music - the kind of bass you actually feel.

And their Computerized Equalizer/Analyzer can provide an accuracy of tonal balance in a listening area never before possible.


dbx linear decibel companding process

The linear decibel companding process, originally developed by dbx for professional tape noise reduction.


dbx vs. dolby

Reduction of noise by three NR systems

Last modified: 20-Aug-2002