MOTU 896HD driver problem

Jun 30, 2008 at 9:19pm

MOTU 896HD driver problem

I’m using a MOTU 896HD to have 8 microphone channels input. I would like to use a sampling rate of 16-kHz, but the CoreAudio MOTU 896HD Driver only has 44.1-kHz and up as options. Does anybody know either a new driver solution, or any other way of getting to my desired sampling rate?

One solution that I’ve already tried that doesn’t seem to work well is to sample at 48-kHz and then just take every 3rd sample. The resulting audio is fairly choppy and doesn’t sound right.

Ideas?

#38674
Jul 3, 2008 at 4:11pm

Evan Ettinger schrieb:
> One solution that I’ve already tried that doesn’t seem to work well
> is to sample at 48-kHz and then just take every 3rd sample. The
> resulting audio is fairly choppy and doesn’t sound right.

You need to filter first, or Nyquist will bite you…
I’d put up a steep fft based filter, and then feed it into a poly~ to
downsample…

Don’t expect the hardware to be capable of doing the filtering. There is
a reason why the driver doesn’t allow it…

Stefan


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#135048
Jul 3, 2008 at 4:53pm

The part that bothers me most about this is that in audacity, or using portaudio, the option to sample at 16kHz is available. Why isn’t this available in Max?

#135049
Jul 3, 2008 at 6:06pm

Do you have a particular technical reason for wanting to work at a sampling frequency of 16 kHz ?

If it’s only for getting a 16 kHz sound quality, how about recording to any upper sampling rate and then process your recording into a downsampling FX (I think there is a Max/MSP object that does this) or a lowpass filter ?

#135050

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