RPi Easy SD Card Setup - eLinux.org

Speaker-test -c 2 -s 1 -t wav -W /usr/share/sounds/alsa -w Front_Center.wav
should be heard on the left speaker. But note that the command speaker-test seems only to
like mono wav files, and seems not to play stereo wav files.
The command aplay plays 2 channel stereo wav files in stereo sound without problem
(provided they last longer than the time it takes the TV to unmute and remute). A helpful
example I found is the stereo file LRMonoPhase4.wav at the Kozco web site [2]
(http://www.kozco.com/tech/soundtests.html)
Sound does not work at all, or in some applications
In Debian Squeeze, sound is disabled by default because the ALSA sound driver is still
"alpha" (not fully tested) on the R-Pi. To try out sound, from the command prompt before
"startx", type
sudo apt-get install alsa-utils
sudo modprobe snd_bcm2835
On Debian Wheezy, snd_bm2835 is enabled, by default, do that step is not necessary.
Next try:
sudo aplay /usr/share/sounds/alsa/Front_Center.wav
By default output will be automatic (hdmi if hdmi supports audio, otherwise analogue).
You can force it with:
sudo amixer cset numid=3
where n is 0=auto, 1=headphones, 2=hdmi.
With recent firmware, you can build hello_audio with:
cd /opt/vc/src/hello_pi/
./rebuild.sh
cd hello_audio
With older firmware
cd /opt/vc/src/hello_pi/hello_audio
make