mixer settings for voice recording?

H. Rosmanith moko at wildsau.enemy.org
Tue Jul 29 15:34:51 CEST 2008


I've got my brandnew neo freefrunner just yesterday, and
have a question about it.

I logged into the ... device via ssh and copied some file
to the audio device, like "dd if=/dev/urandom of=/dev/dsp bs=1k count=100"

This will produce some noise, as expected.

Now I'd like to copy some data from the microphones, and I first
check what's coming in from the device using "od" like in:

    od -x /dev/dsp

but this only produces a permanent stream of 0x80 - a flat, silent 
line (He's dead, Jim!)

I played around with alsamixer settings, un-muted all entries,
be they playback or capture, and maxed the volume. I randomly
changed entries which allow multiple selection, e.g. Mic1, Mic2, Mic3
and so on.

The maximum I got was a high-pitched sinus-sound (obviously resonance frequ.),
but the output of "od -x" never changed.

So, what is required to make the dsp-device delive audio-data?

Q: The hardware does support this, right?

Q: Is it a audio-driver problem, e.g. the alsa-device-driver for the chip
   doesnt support audio capturing?

Q: Is it a problem with my mixer settings? If so, which are the correct
   mixer settings?

kind regards,
H. Rosmanith

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