[linux-audio-user] Audio interface recommendations

Jon B 30plxf602 at sneakemail.com
Tue Jan 18 11:31:07 EST 2005


Interesting.  So that one is responding past 20 kHz?  What program are
you using?  You can't just connect the output back to the input and do
the test that way?  Should then test at a low sampling rate like 11025
Hz, and see if it aliases.

> Interesting.
> I did two measurements @96000, first with a tone sweep, and then with
> white noise. The results were:
> 
> Tone sweep:
> www.geminiflux.com/Stuff/snapshot1.png
> White noise:
> www.geminiflux.com/Stuff/snapshot2.png
> 
> The card being use was Echo Mona Laptop, the microphone a Shure Beta58
> (which might account for the weird behaviour), and the speakers were
> Mackie HR824.
> I'll give it a try next week with a better microphone.
> Cheers,
> Andres
> 
> Jon B wrote:
>
> >I realized why they do this.  With variable sampling frequencies,
> >44.1, 48, 96, you would need different filters to get the best out of
> >each one.  So they just do 20 once and throw away the extra bandwidth.
> > So does that mean they will alias at sampling rates like 11025?  This
> >could be tested, too.



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