24/96 upsampling vs. 24/192 upsampling vs. no upsampling?

Question: Does an old 16bit CD really have all the information on it (beyond 16bit) so you can change it to 24bit?? This has always confused me about unsampling?

Dweller is confusing "upsampling" with "resolution enhancement". Upsampling means that we resample the input stream (i.e. 44.1 khz CD) at a higher sampling rate, retaining the original 16 bit word length.

If the higher sample rate is a non-integral multiple of 44.1 (i.e. 96 or 192 khz) one must calculate totally new sample values for each point in the new data stream. If the higher rate is an integral multiple 044.1 (i.e. 88.2, 176.4 etc.) then the original samples become a direct part of the new output stream. This is standard oversampling. Again we retain the original 16 bit word length.

Resolution enchancement is an attempt to extrapolate extra data beyond the original 16 bits in the CD data stream. There are 3 ways which may be used together. First, the digital reconstruction filter will generate extra bits as part of its calculation process. These may be used to extend the signal. Second the designer may add some form of dither (a small amount of digital noise) to create extra bits beyond 16. BTW, note that any didgital audio systems requires a certain amountof dither to achieve good linearity at small signal levels. Third, the designer may use a software algorithm to guess at the extra bits by analyzing the original 16 bit data stream.

Many manufacturers really mean upsampling + resolution enhancement when they advertise upsampling. They are independent processes, however.

In short, a CD encoded in 16/44 has no information beyond those bits. Interpolation is not finding something that's there; it's guessing at the existence of something and adding it.
24/96 encoding on the other hand is a real advance, and of course a 24/96 dac is necessary to fully decode these recordings. However, other factors in a dac design may not allow all those bits to come through as musical information: if the dac is not well designed, noise, for example from the power supply, or jitter, will nullify the advance represented by 24/96.
That is partially why a well-designed 20-bit CD player w/a quiet and dynamic dac and output stage will probably beat a cheap nasty DVD player with a 24/96 dac.

I think that most people would agree that the designer's implementaion of the technology is more important than the technology. Many people rave about some 24/96 or 24/192 designs, but some rave about the non-upsampling designs of Audio Note or Sakura.

It's probably best to listen to as many as possible in your price range. Most will sound different from each other...even the units that upsample to 24/96. It really comes down to the design and your personal preference.

Thanks for keeping the informative posts coming.

I found some interesting links abount Perpetual Technology digital gear:

http://www.jeffchan.com/audio/p-1a-vs-d2d-1.html

http://www.jeffchan.com/audio/daif.html

This is the first negative stuff I have read about Perpetual that seems credible.