Raspberry Pi – sound HOW-TO

Here are a few pointers on how to make the sound work on Raspberry Pi. I’ve gathered these bits and pieces along the way of using this tiny computer.

First of all – Arch Linux for ARM (i.e. alarm) is the best distro I’ve used on RasPi so far. Lightweight, starts in just a few seconds, has a lots of packages and you can install it just the way you want. And this is also the distro for which I am writing this short How-To.

How to add the sound module

To make the system see the integrated sound card you need to load the appropriate kernel module. Like so:

sudo modprobe snd_bcm2835

To check whether it is loaded, just check the output of lsmod. The command written above has to be executed every time the system starts. To make it “stick”, add the module to the list of automatically loaded modules. That is create a new file  /etc/modules-load.d/sound.conf containing just a single line:

snd-bcm2835

That’s it. The sound module should now load every time you start your RasPi.

How to install Alsa

Most of the programs will be able to output sound using Alsa. To install it, issue this command:

sudo pacman -S alsa-utils alsa-plugins alsa-lib alsa-firmware

Now you can run speaker-test and it should produce a nice white noise on your speakers.

How to enable analog sound

If you want to select which sound output should be used (HDMI or analog 3.5mm jack), the command to use for Alsa and analog output is:

sudo amixer cset numid=3 1

Or substitute the last “1” for “2” if you want HDMI.

How to make VLC or mplayer work with Alsa

If you are getting messages like this:

alsa audio output error: cannot commit hardware parameters: Invalid argument
jack audio output error: failed to connect to JACK server
main audio output error: no suitable audio output module

All you have to do is fix the sound card configuration via creating a simple *.conf file: /etc/asound.conf with the following content:

pcm.!default {
   type hw
   card 0
}
ctl.!default {
   type hw
   card 0
}

For more info, take a look at this: http://elinux.org/R-Pi_Troubleshooting#Sound