ALSA
ALSA or the Advanced Linux Sound Architecture provides audio support for Linux. It is a replacement for the old OSS linux sound system. The Alsa-utils package contains both the Alsamixer and Amixer utilities. Various linux distributions once used the Open Sound System, or OSS until ALSA superseded it. ALSA provides kernel driven sound card drivers and bundles a user space driven library for application developers.
You can control the audio properties of your sound cards through:
- Alsamixer-The graphical interface for ALSA
- Amixer-The command based utility for ALSA
CLI Utilities
alsamixer
ncurses based utility with visual representation of various levels.
alsamixer
Enable the microphone: switch to the Capture tab with F4 and enable a channel with Space.
mixer
Command line, operation performed per command.
amixer -c [card-number] set [control] [value]
To see what controls you can manage
amixer scontrols
If you are sudo there are more controls available
sudo amixer scontrols
apulse
The apulse utility lets you use ALSA for applications that support only PulseAudio for sound.
aplay
Alsa play - play an audio file
arecord
We can test the default audio input device, or the only audio input device on a simplistic configuration
arecord -vvv -f dat /dev/null
Watch while the audio input levels are displayed as a percentage.
We can specify an audio input device
arecord -vvv --device="hw:1,0" -f dat /dev/null
You can display a list of CAPTURE Hardware Devices. To figure out what audio input device is at hw: card,device use the following command
arecord -l
The output look for "Card X" and on the same line "device X" to know the card,device combination to specify.
speaker-test
as the name implies