aaronji, to your previous question, if a recording "fits" within 16 bits then by definition there is no benefit to be gained by extending it to 24 bits, as long as you don't alter the recording otherwise.

If, however, the recording really uses the full range of the available 16 bits (I think it happened to me only once ever, at a percussion ensemble concert), then if you wish to do certain kinds of processing on it, there might be a tiny, tiny, tiny (and almost certainly not audible) theoretical advantage to adding another bit or two. To make the difference even potentially audible, you would need to play back the recording at a level allowing you to hear those bottom bits, and then the highest-order bits would be about 100 dB louder, which is not gonna happen in a critical listening situation.

--You can view the digital samples as signed integers as you want, but then you end up with full scale = +32767 or -32768, which are rather arbitrary numbers if you're not a binary geek. To me it makes more sense to view the samples as binary *fractions*, i.e. analogous to decimal fractions such as 0.45 or -0.234, with the bit values based on the series 1/2, 1/4, 1/8, etc. -- then full scale can be reckoned either as +/- 1 or, if you prefer, +/- 1/2 so that the entire range is then 1 from peak to peak.

In either case, because of the particular binary notation involved (so-called "two's complement" arithmetic), the 0 sign bit for the value 0 places that value in the positive half of the range. So there is one possible extreme sample value in the negative direction that is one step farther than exists on the positive side. This is equivalent to saying that in integer arithmetic (say, for an eight-bit byte), the possible values are from -128 through 0 to +127.

Many years ago I worked with a computer system (the "Adage Graphics Terminal") that used "ones' complement" arithmetic; it was weird because it had both +0 and -0 that were logically distinct values, even though they were quantitatively equal. And its maximum positive and maximum negative values were identically far from 0. But that type of arithmetic was rarely used even then, and by convention PCM audio is always twos' complement.