Linrad support: Install snd-aloop under Debian and Ubuntu
(Dec 14 2010)
The Linux sound system ALSA has a mechanism by which the output of one program can be sent to the input of another program. It is similar to VAC (virtual audio cable) under Windows. By installing snd-aloop one will get virtual soundcards that can be opened as the output of one program and as the input of another program. Unfortunately this feature is not (yet?) enabled in the standard distributions.

This page describes how to install snd-aloop under Debian and Ubuntu.

Install under Debian squeeze or sid with the kernel 2.6.32-5-686 (December 2010.)

Log into your system ar root.

Install the package alsa-source
apt-get install alsa-source

Go to the /usr/src directory
cd /usr/src

Unpack the alsa source tarball
tar xvfj alsa-driver.tar.bz2

Install the linux headers
apt-get install linux-headers-2.6.32-5-common
apt-get install linux-headers-2.6.32-5-686

Descend into the the alsa source three
cd /usr/src/modules/alsa-driver

Configure alsa-source to build all or if you know what you want, selet only what you need. (all is the default so you can skip this step.
dpkg-reconfigure alsa-source

Produce the new alsa package
fakeroot debian/rules binary_modules KSRC=/usr/src/linux-headers-2.6.32-5-686 KVERS=2.6.32-5-686

Install the new alsa package
dpkg --install /usr/src/modules/alsa-modules-2.6.32-5-686_1.0.23+dfsg-2_i386.deb

Install under Ubuntu.

sudo add-apt-repository ppa:ubuntu-audio-dev/ppa
sudo apt-get update
sudo apt-get install linux-alsa-driver-modules-$(uname -r)

This procedure installs the latest alsa version 1.0.23 (December 2010) with the snd-aloop driver under Ubuntu 10.04 and Ubuntu 10.10

Make sure the snd-aloop.ko module is loaded at boot time.

Edit or create a file /etc/modprobe.d/alsa-base.conf At the very end of the file add something like the following lines
options snd_xxxxxxx index=0
options snd_yyyyyyy index=1
options snd_aloop index=2
See the file z_ALSA.txt in the linrad package.

Edit the file /etc/rc.local and add a line
modprobe snd-aloop

reboot your system

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