Question about CD 'Resolution'

how can you tell what a cd players resolution is I see things like '24 Bit Conversion' and 'Digital Processing 24-bit' and '24/96 Dac' but then you end up finding out that the players real 'Digital Resolution' is only in actuality 20 bits.

Some companies only give the number of Bits used in the DAC, but how can you find out what the actual resolution is?
Listening to it. No other way makes any sense - the concept of sub-optimalisation.
however way you cut it, the cd format (red book) is limited to 16 bit/44khz resolution. that is the physical limit of the software. that little shiney disc can only hold that info.

in general, there are 2 ways to "enhance" or alter the amount of "resolution" that actually comes out of the analog output of your cdp or dac.

first, processes can be imbedded into the 16/44 signal that can be interpreted by the appropriate filter/dac to "noise-shape" or "enhance" the sound; the best known of these is HDCD. another would be Dolby Pro-Logic. these methods don't add data but give the dac clues to "shape" or "adjust" the sound. they don't ADD resolution.

the second, and currently popular method, is over-sampling and up-sampling. these methods take the 16/44 data and either add bits to the 16 bit word (commonly to 18, 20, or 24) or add more samples in between the 44khz samples (usually, but not always in multiples of 44khz; 88khz, 96khz, 172khz, 192khz, or even 768khz). these methods are attempting to reduce the negative effects of the 20.5 khz digital filter on red book, reduce noise, or add "ease" or "presence" to the sound. none of these methods ADD resolution. they may make the sound more listenable or enjoyable. and therefore "better".

i have dramatically oversimplified my explaination but the fact is that no format can create information not on the original software. they can only manipulate data and change the perception of how it feels or sounds.

so all cd players and dacs input the same resolution, manipulate the data to some degree and output an analog signal. i have seen very little corelation between the ultimate sampling rate of their chosen manipulation scheme and performance so far (but many disagree with me).

there are certainly differences between resolution of various cdps, transports and dacs. but these differences have to do with the quality and execution of the designs, and not creating "new" resolution from 16/44 software.
Who cares?! I know that on the surface, this might seem like an important bit of information, but build and component quality and circuit design are the import factors. Musicality, and sound quality are what we're all looking for. Read the forums, listen to as many units as possible (piano and violin will let you know how good the Sonics of a CD unit really are). Don't get caught up in marketing "hype"...let your ears be the judge! Happy Tunes!
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I have read that one reason higher bit DACs outperform 16bit even though the data is 16bit, is because a 16bit DAC is actually less than 16bit in actual use. Some data is lost or cut off. The higher bit DACs give the data more room, just like adding processing power or memory to your computer. There are some DAC experts like Jeff in Montreal who could probably answer this better.
Overall design is more important than sample rate. New 24/96 recordings may sound better on 24/96 players but there are not that many available.