From: kong@leland.Stanford.EDU (Kong Kritayakirana)
Subject: CD Sound Quality
Organization: DSG, Stanford University, CA 94305, USA
Date: Sat, 19 Dec 92 11:37:49 GMT

> 99% of the audio buying public has already been suckered into
> thinking that CD sound is the be-all end-all of sound quality.  They are
> mistaken.     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

   Although we can definitely engineer a better medium for holding music, I
   think we can say we have perfectly satisfied our ears with 44.1kHz x 16bit
   data for each channel. Who the hell can tell the difference between 96dB
   (of 16bit) and any other higher figure achievable using more bits, of
   dynamic range? This is obviously not possible even in anechoic chamber
   whose background noise is about 30dB above our threshold of hearing. We
   need to find a way to usefully exploit what can be achieved with 16 bits,
   eg., proper dithering and setting the maximum lelvel on the disk to 0dB,
   of course. Also, oversampling during ADC (128x or 256x) and DAC (8x or 16x)
   is necessary to keep non-ideal characteristics of ADC and DAC out of the
   audible range. People CANNOT hear the difference between 15-bit and
   16-bit encoded music. Certainly with oversampling techniques the 44.1kHz
   bandwidth is wide enough. Or you could use tweako's argument about our
   "ability" to hear things beyond 20kHz. Jitter is not a problem during ADC,
   and we definitely can cure jitter by putting the crystal of the DAC system
   IN THE DAC box, not in the transport box. The whole jitter scene then
   becomes a nonissue.

   I have not yet heard/seen enough about DCC and MD to comment about the
   subject. But given that there are proofs that we can do about 3:1
   LOSSLESS compression/decompression in real time, we can fit in a lot more
   music on a 5-inch CD using the present laser/optical technology.

   I think the thing where there can still be a LOT of improvements is in the
   transducers and related things, ie., microphones, recording techniques,
   speakers, and room setup. Ever been to a REAL orchestra? At one time I went
   to see Carmina Burana and when I got home, I put my Carmina Burana CD on
   to see how close it is to the real thing. I felt like I want to throw
   my hifi system out the window. My "wonderful" sounding system does not come
   any close to the real thing, although it got high praises from my audiophile
   friends. Do you think CD is to blame for this? Haha, too bad it sounds even
   worse on analog records.

   I hope we beam out energy into the area where improvements can be made
   with reasonable cost, not into things like $200000 digital interconnect and
   $50000000 MagicBrick(TM) that "suppresses" vibration in components.

   Flames? Send me email. I will be out of the country for 2.5 weeks and will
   not be able to read responses posted on the newsgroup. Sorry if the turn-
   around time is long.

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Kong Kritayakirana                          kong@leland.stanford.edu
EERA STAR Lab                   'An optimist believes we live in the best of
Stanford University              all possible worlds. A pessimist fears this
Stanford, CA 94305               is true.'     -- Advanced Murphology
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