[linux-audio-user] Audio interface recommendations

Andres Cabrera andres at geminiflux.com
Wed Jan 19 18:16:17 EST 2005


Of course, I hadn't thought of connecting the outs to the ins...
Here are the results:

www.geminiflux.com/Stuff/96000.png
www.geminiflux.com/Stuff/88200.png
www.geminiflux.com/Stuff/48000.png
www.geminiflux.com/Stuff/44100.png
www.geminiflux.com/Stuff/22050.png

It seems the anti-alias filter depends on the sample rate, which is cool.

Cheers,
Andres


Jon B wrote:

>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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