Why does upsampling use 192kHz instead of 176kHz?

[HaLo6]

If CD audio is native at 16/44 why does so much hardware upsample to 192kHz (and for that matter 96kHz). Wouldn't it be better to upsample to 176kHz (or 88kHz) as its an even multiple of 44, since 192 is an even multiple of 48 (and 96)?

Just a quick question out to the crowd!

[pilli]

CD is actually 44.1 KHz, so it wouldn't be exactly 176...

Have a look at this about how that was chosen:
http://www.cs.columbia.edu/~hgs/audio/44.1.html

and here for an anecdote:
http://stason.org/TULARC/entertainme...z-samples.html

(It's good that Karajan wasn't much of a Mahler conductor,
or to fit *that* ninth symphony, we'd be living with 32 KHz or
have CDs of 10 inches diameter...)



-

[pilli]

...longer version here:
http://www.exp-math.uni-essen.de/~im.../beethoven.htm

_

[mr.duck]

Originally posted by HaLo6
If CD audio is native at 16/44 why does so much hardware upsample to 192kHz (and for that matter 96kHz).

192 is a higher number so must therefore be better. Numbers + Marketing = profit

This is DIYAUDIO so we have no room for that. You can upsample however you like. Come back and tell us of your results.

[HaLo6]

yeah I knew it was 44.1 and subsequently 176.4... I was just philosophically wondering why upsampling isnt an even multiple... thats all...

[Floric]

The usage of 44.1 kHz sampling is a speciatity of the audio cd. All the other equipment especially the professional ones use 48 kHz.

192 kHz is a multiple of this (more "common") frequency.

Regards

Flo

[Javin5]

Oversampling uses an integer factor. Upsampling is a different (and more complex) process where you can basically operate the DAC asynchronously at any frequency and the ASRC (Asynchronous Sample Rate Converter) converts the initial 44.1 sample rate accordingly.

Kurt

[HaLo6]

Originally posted by Javin5
Oversampling uses an integer factor. Upsampling is a different (and more complex) process where you can basically operate the DAC asynchronously at any frequency and the ASRC (Asynchronous Sample Rate Converter) converts the initial 44.1 sample rate accordingly.

Kurt

Cool thanks! So oversampling requires an even interval but upsampling the frequency isn't an issue.

[tritosine]

Originally Posted by HaLo6

Cool thanks! So oversampling requires an even interval but upsampling the frequency isn't an issue.

not true at all. You can oversample by non integer numbers, like 384khz result out of both 44-48khz , -Think taking samples out of a FIFO buffer and you only want a single dsp clock. Upsampling term was coined because its supposed to do the heavy lifting before the builtin chip oversampling , and filter jitter as well. Also more refined processes can be tought of than an ASRC, the upsampling possibilities are wide and not by any means the asynchronous manner is necessary .

[fmak]

Originally Posted by Floric

The usage of 44.1 kHz sampling is a speciatity of the audio cd. All the other equipment especially the professional ones use 48 kHz.

192 kHz is a multiple of this (more "common") frequency.

Regards

Flo

This does not mean that 192k from 44.1 is right.

Most experienced audiophiles find 176.4 better sounding than 192 k when CD is upsampled. I have had long experience of this with all kinds of gear.

Assynchronous upsampling of any kind is not desirable.