[linrad] External soundcard experience

["Arie Dogterom" <pa0ez@xxxxxxxxx>]

Hello All,

The recent question from SM5BSZ about using a notebook for linrad brought me
to some experiments.

I have a laptop with an integrated soundcard ( VIA 686) . As external input
it only has a MONO mike input.

I got access to an USB external audio card, the Soundblaster MP3+ usb,
specified as being 48 kHz/16bit. My SuSE 8.2 system has ALSA integrated and
it does not like ALSA to be deleted. So I use Alsa and in practice this
works very well for the internal card. Probably it also works with the
kernel audio driver for usb but in my case I could not getting it running.
The automatic setup of alsa, however, does not find the USB card, but the
Yast setup of SuSE lets one setup any driver alsa provides. I did setup the
driver "snd-usb-audio" and indeed the external card works.
Setting up the mixer, however, is not too good. In fact the only mixer
programme which is able to control the usb card is the gamix programme of
alsa. Every other mixer-control tested does not work . The indications
printed on the mixer control, however, are not too useful. But after some
experimenting I found out which is what and now I can use linrad ( I still
use version 0.56)as it should be although I do not yet have made an I/Q
mixer system , but the audio filtering runs well and I even am able to use
one card as input and the other as output. I, however, do not know how to
set up different sampling frequencies for the two cards. Linrad simply does
not give me a chance.

This information might be useful for some of you. There probably are cards
which are better supported ( mixerwise) by linux but this card has a
reasonable price ( EUR 49,50 dilivered at home)

73

Arie, PA0EZ

LINRADDARNIL