Linrad support: Install sound
(June 13 2003)

Try the sound system that is probably in place already

Most Linux distributions already have a sound system installed and configured during the normal Linux installation procedure.

Start linrad and see what happens!!

Since this is the first time on a new computer linrad must get information about your hardware before entering normal operation modes. The very first time you have to press S to select a screen to allow switchover to graphical mode under svgalib.

You will not be able to make any serious mistakes and more or less any parameter selection should work. This link: select screen, mouse speed, A/D and D/A devices and speeds etc. gives some explanation and hints what to do if there is a problem.

If you were able to select sound devices your system is ok and you can press A on the linrad main menu.

Again, this is the first time on a new machine and linrad wants you to specify a lot of parameters. Just press enter to all the parameter selection screens and see what happens. You should get some windows on the screen and probably you will see some kind of spectrum in the wide graph. What you see on the screen is probably noise from the microphone input.

Connect a signal to the microphone input and watch the probably far too high signal level on the spectrum display. You will most probably hear the signal in the loudspeakers because sound boards are typically configured by default to route the input directly to the output. You are supposed to want to listen to the music while recording it to the hard disc....

Use the sound mixer program that belongs to your sound system

linrad does not try to change any settings within the audio board(s) except sampling speed. The system provides a sound mixer program, usually as a graphical program that you run under X11. The sound mixer displays volume controls and switches. There is a switch to select line input to the A/D converter and another switch to disconnect the loudspeaker from the input.

Place all volume controls at 50%. At this stage it is enough to make sure you can get signals into the linrad program and out to the loudspeaker after processing. Wait to set the analog signal level and A/D board gain until uou have selected the mode dependent parameters.

At this stage, with too much signal at the input, you should be able to see that the signal now originates in the line input. The loudspeaker should be quiet until you press the right mouse button somewhere on the wide graph (blue dB scale). You may have to bring up the red bar (volume control) at the left side of the baseband graph (green dB scale) to hear something in the loudspeaker. If you can get some sound the sound system is ok and you should select reasonable processing parameters before worrying about volume control settings.

In case sound does not work, chances are good that it will if you install OSS - or at least it will be more transparant what the problem is. Maybe your sound board does not support duplex?

Installing OSS

Get OSS from
For actually using the dsp package you will have to purchase a licence but limited use is free.

In case you want to install Linrad on an elderly computer or if you want to use an old Linux distribution for other reasons, the OSS package you can get from may not work. In case you get a message "kernel not supported" when trying to install OSS, try this old version oss393m.tgz (1366384 bytes) which should work with any Linux kernel version since 2.2.0 but it requires that the kernel include files are available and properly configured. oss22x.tgz (1370106 bytes) is another old OSS version which I have used extensively in the past. Please note that 4Front Technologies doesn't give any support for these versions any more.

ALSA Is fully compatible to OSS according to specifications. OSS with accompanying licenses should not be needed unless you want to use boards (i.e. Delta 44) not supported by other sound systems.

Create a directory /usr/oss and copy the ossxxx.tar.gz file to it. Go to this directory, uncompress and extract the files:
cd /usr/oss
gunzip ossxxx.tar.gz
tar xvf ossxxx.tar

Type: ./oss-install. Allow the installation program to do changes for you and install OSS files into /lib/oss.

After having installed OSS you should recompile linrad. Run configure and make to allow linrad to use the include files belonging to OSS.

The include files are compatible as far as I know, but just in case... Only if you have a 24bit audio board the recompilation is really required.

SM 5 BSZ Home page

Linrad home page