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. >>> >>> > > > > >
