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The -90 dB argument and the "H" word.

Jriver has put themselves in a catch 22 situation. From various posts by Mr. River on forums and web sites the basis for the "Hoax" claim is their dogmatic belief in the religion of "Bits are just bits". If they believe in this dogma, then they are incompetent. Good engineers do not dismiss claims of sonic differences based on lack of measurements and/or inability to personally hear these differences. If they do not believe in this dogma then their claim of "hoax" has no basis and this statement is unethical. Actually, making such a statement in public would be questionable ethically, even if JPlay were a hoax, unless they were prepared to back it up with evidence.

Differences at low levels can be audible under certain circumstances, depending on the recording, the equipment and the listener. Given numerous people who hear differences, such as effects of playing FLAC vs WAV files, that would be inaudible if "bits were really just bits", a competent engineer would be asking himself, "What is going on? Why are other people hearing differences and I am not? If they are right, how am I going to develop and market a quality product?" (This is the situation that one of the designers of the SABRE chip had when audiophiles reported artifacts in an early version of the chip that the designers could not hear and could not measure. The result was an investigation that showed that they were hearing real effects, a new measurement technique that demonstrated how to quantize sigma-delta modulator performance, and ultimately a new version of the modulator that sounded better.)

As to effects at -90 dB supposedly being inaudible. This is nonsense. Peak sound levels can be over 20 dB greater than average sound levels, in some recordings over 30 dB greater. Low level effects are not as low as you may think. Another factor relates to how noise levels are measured. If they are measured broadband then one can hear distortion that is as much as 20 dB below the noise floor. Alternatively, if the -90 dB was taken from a spectrogram plot, it may correspond to a noise level that is as much as 30 dB louder. For playback of acoustic music recorded in a concert venue there will be "reverb tails" that go all the way down to the threshold of hearing. Peak sound pressure levels at Mahler symphonies have been measured at over 120 dB, even though the average sound pressure levels at these brief fortissimos may be only 95 dB.

To put matters further in perspective, I once sent back an 88/24 needle drop file. I had been editing a portion of it. However, the person who got it said that I had "completely trashed" the file. I thought I had left it unchanged except for the ticks and pops. It turned out that my software had converted the file from 88/24 to 88/32floating point. When I sent the file back, I converted back to 88/24 with dither enabled. As a result, low order bits had been changed. Most of the differences were +1 or -1 in individual samples, but there were some that were +2 and -2. The RMS difference between these two files was -136 dB, and yet an audible difference was reported.

I no longer worry very much about the noise floor or Redbook recordings, or the sound quality thereof. I consider this format obsolete and incapable of state of the art playback. This was my inital belief when CD players first came out and although there have been improvements in the recording and playback technology this is still my belief. Anyone who doesn't appreciate the inadequacy of the 44/16 format is unqualified to comment to the issues under discussion because they lack the ability to hear what is going on. If one of these people is selling audio playback software, their only sensible course of action would be to keep their mouth shut. (It would have been appropriate for Jriver to politely say that systems with JPlay installed were not supported because of potential system interactions. No need for the "H" word.)




Tony Lauck

"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar


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