Hardware Reference
In-Depth Information
As you can see, presently there's only one card—number zero, the audio core of the
Pi itself. When we plug in a new sound device, it'll be assigned the next available
card number, starting at one. Type in the following command to list the contents of
the
asound
directory:
pi@raspberrypi ~ $ ls -l /proc/asound
The black/white names are files that you can output with
cat
. The blue ones are
directories, and the cyan ones are
symbolic links
, or
symlinks
that just point to
other files or directories. You might be puzzled by the
total 0
output. Usually it'll
tell you the number of files in the directory, but because
/proc/asound
is a special
information-only directory where the file sizes are zero, it appears empty to
the
ls
command.
Directory listing of /proc/asound
Controlling the volume
It's time to make some noise! Let's start up
AlsaMixer
to make sure the volume
is loud enough for us to hear anything, using the following command:
pi@raspberrypi ~ $ alsamixer
You'll be presented with a colorful console application that allows you to tweak
volume levels and other sound system parameters.
