In article , "Arny Krueger"
wrote:

That there are 8 extra bits per sample is an
inarguable fact that we can all agree on.

That we can agree on, but how audio behaves because of them we don't.

The 24 bit number is more precise than the 16 bit. True enough. What
that means in audio, however, is that the 24 bit word can describe
smaller values than the 16 bit word, thus signals that are lower in
level.

It means that, but it also means that a 24 bit word describes 255
additional
levels between every pair of levels that can be described by a 16 bit
word.
It means both things. Again, this is inarguable and readily observable in
the real world.

The 16 bit number is already describing 96 dB of dynamic range
just fine.

Psychoacoustically 16 bits does do a fine job, however technically the 24
bit word codes 255 additional levels between each pair of levels
described by a 16 bit word.

Looking at the system as a whole, dither and all, you gain no advantage
in the top 96dB. You get and extra 48dB below them.

--
Jay Frigoletto
Mastersuite
Los Angeles
promastering.com