[Discuss-gnuradio] Sound card configuration

[John R. Ackermann N8UR]

Hi All --

This may be a little off-topic, but (a) sooner or later I *will* be 
using GnuRadio with this configuration, and (b) I figure the folks here 
are quite likely to have been through this exercise.

Anyway, I am trying to get my SDR/spectrum analysis system rebuilt on a 
Linux 2.6.9 kernel and am trying to get the sound system configured.  My 
applications will be GnuRadio, the SDR-1000 software once that's 
release, and of most immediate importance, the "baudline" spectrum 
analyzer software (http://www.baudline.com).

I have two sound devices -- the motherboard's VIA8233, which I only 
intend to use for the occasional song played through the speakers, and 
an M-Audio Delta44 which is going to be the main workhorse.

I'm having a dickens of a time getting everything to work.

First I tried the commercial OSS system from 4Front.  With that, the 
VIA8233 played the test file at about 1/4 speed.  The Delta44 card 
passed all the tests with flying colors, but when trying to run baudline 
I got strange errors about requested fragsize being ignored.

After messing around with OSS for a while, last night I built the kernel 
with ALSA support and downloaded all the Debian ALSA tools, plus 
building the envy24control program from the alsa-tools package at the 
ALSA website.

Now both cards seem to be working properly at the physical interface 
level, but (a) getting both cards working simultaneously is a problem, 
and (b) I can't figure out how to separate the 4 mono inputs from the 
Delta44 into either two stereo pairs or 4 separate channels.

When both cards are installed, it seems that both want to use 
/dev/audio0, and the first card loaded wins.  How do I get each card to 
talk (and listen) through its own device?

Second, what sort of magic do I need to make the individual inputs and 
outputs on the Delta44 accessible?  And, how do I direct a device to use 
them?  Right now, for example, baudline will display the signal from 
hardware input 1, but it doesn't offer me any choice of input other than 
"digital 1" on its device selector.  How do I tell it that there are 
multiple channels out there?  I suspect the answer is in the asound.conf 
or .asoundrc files, but cutting-and-pasting the samples I found on the 
web don't seem to accomplish anything.

Any help would be *greatly* appreciated.

Thanks,

John