[Audio Empire]

On Tue, 30 Aug 2011 03:47:58 -0700, Edmund wrote
(in article ):

On Mon, 29 Aug 2011 23:15:38 +0000, Audio Empire wrote:

On Mon, 29 Aug 2011 04:56:46 -0700, Edmund wrote (in article
):
=20
On Mon, 29 Aug 2011 03:10:45 +0000, Robert Peirce wrote:
=20
I run Pure Music on my Mac. Presently, I use Airfoil to send the
signa=3D
l
over ethernet to my AppleTV. The AppleTV has an optical output to my
DAC. Pure Music and my DAC both support 96/24, but the Apple TV only
does 44.1/16 (or, maybe, 48/16 - hard to find specs). =3D20
I have been trying to find a substitute for the AppleTV, but so far
all I have got is the Squeezebox Touch. I say "but" because it has
its own software that resides on the Mac and I have not been able to
find out i=3D
f
it can receive input from Pure Music or not. Does anybody know? =3D2=
0
The web site suggests the Squeezebox can read any file on the
computer, which is great, except Pure Music already does that and
allows many useful manipulations. For example, it will accept up to
384/32 and downsample it to 96/24.
=20
I wonder what happens to the anti alias filter in that case.
=20
Edmund
=20
=20
You would certainly have to move the filter up in frequency in order to
use that extra bandwidth,=20

I don't think one get extra bandwidth when you DOWNSAMPLE 384/32 to 96/2=
4,
and the filter should be corrected to 40 kHz or so.

No one said that you did. In fact no one mentioned downsampling in
conjunction with this question at all.

otherwise the filter would simply treat the
signal like any other digital audio stream and start to roll-off the
frequency response above 22 KHz. What the use of high sampling rates
does is to move any quantization noise further out of the passband as
the sampling rate increases. Whether this is of any practical
consideration is debatable. Double-blind tests seem to show that this i=
s
no real consequence, but some will hotly debate the point.

And we can debate for a long time since there are no recordings recorded
with much higher frequencies then 22kHz.

I don't think that's true at all. Any recording mastered at 48 KHz, 88.2 KHz,
96 Khz, 176.4 KHz, or 192 KHz (not to mention 384 Khz or DSD) certainly have
info on them above 22 KHz. The frequency response plot that came with my
Avantone CK-40 stereo microphone shows significant (albeit attenuated) output
to slightly above 30 KHz and my mixer is flat to 50 KHz. I know that it's
there on my DSD masters and on the 24/96 copies that I run-off for my
clients.

I for one am still waiting for such real high res recordings.
( don't know about SACD since I cannot make such files visible.... yet )

Of course, you won't find that kind of frequency response on analog mastered
recordings or on any Red Book CD, for that matter. That should be obvious.