Re: What's the use of a 192 kHz sample rate?

> This is not rocket science.  The differences may not be audible to
> you, but they exist and they are well understood.  I'll give you a
> hint; do you know what phase distortion is?

The 20KHz low-pass FIR filters that they use in all modern CD/DVD players 
are phase linear.

> Also, I would like you to explain what is wasteful about a 192 kHz
> sample rate.  How much money does it cost to use 192 kHz instead of 96
> kHz or 44.1 kHz.  What time is involved?  How much extra energy does
> the higher sample rate use?  Are you aware that there are virtually
> infinite amounts of bandwidth not being used every second?  What
> difference does it make if DVDs underutilize a bit more?

The only reason to use anything higher than 44.1KHz for consumer playback
is 
marketing, and evidently, they have bandwidth (storage) to burn, so it 
doesn't cost them much.

> I am working on a circuit that uses a 192 kHz CODEC to process 1 kHz
> signals.  Of course I am not using it at 192 kHz, so am I wasting
> bandwidth still?  Or by using an 8 kHz sample rate, am I conserving
> bandwidth and deserve recognition? I like the idea of being "pink" (as
> in noise) by conserving precious bandwidth.  Actually, I can't wait to
> get the thing out on the open road and open it up!  I want to put the
> pedal to the metal and sample at the full 192 kHz to see just what
> sort of analog bandwidth these CODECs really have!  I'm not actually
> sure they will produce higher than about 40 kHz at the analog output.
> I'll have to hack away the 1 pole filter I added to the input and
> output.  It limits the frequency range to a paltry 30 kHz or so.  I
> may not hear the difference, but my scope can "see" it!

Okay, if you are still working with analog filters, then you need more
room 
for the transition band. Digital FIR filters get you much closer to the 
theoretical limits much more easily and predictably. And they stay in spec

with temperature and age.

> BTW, if you aren't looking at your monitor or you aren't sitting close
> enough to see every pixel, are you wasting bandwidth on your video
> signal?  Actually, that is an excellent analogy.  If you limit the
> video bandwidth to half the pixel rate, what difference will you see
> on a CRT display?

The difference here is, video bandwidth is chosen for a particular viewing

distance, and if you are within (or nearer) the optimal distance, higher 
bandwidth is easily perceptible. Not so with excessive audio sample rates.

> Finally, why do you see the advantage of using 96 kHz sample rate and
> not 192 kHz?  Isn't 96 kHz wasting bandwidth?

Yes, very much so. I daresay you won't find a lot of 96 or 192KHz sample 
rates where bandwidth is at a premium (broadcast, satellite or streaming 
media). Quite the reverse; they'll be looking for ways of reducing the bit

rate. But if you have bandwidth (storage) to burn, and a lot of 
unsophisticated consumers who think bigger is better, then 96 or 192KHz it

is. Not because good engineering demands it, but because marketing 
departments know consumers are gullible. The original CD spec was pretty 
much optimal from an engineering perspective. It delivers just as much as
it 
needs to, and not much beyond. It was beautifully engineered. Many of the 
original CD players (and recorders) did not actually meet the spec very 
well, nor did recording engineers and producers understand how to work
with 
the new medium, which gave CDs a bit of a black eye. But the theoretical 
design was quite optimal.