amixer & aplay

@ Usage
# amixer
...
Simple mixer control 'Playback',0
  Capabilities: volume
  Playback channels: Front Left - Front Right
  Capture channels: Front Left - Front Right
  Limits: 0 - 255
  Front Left: 255 [100%]
  Front Right: 235 [92%]
...
Simple mixer control 'Speaker Playback Off',0
  Capabilities: enum
  Items: 'All off' 'Left only' 'Right only' 'Stereo'
  Item0: 'Stereo'
...

@ Example
1. Power On/Off
# amixer sset "Speaker Playback Off", "Stereo"
# amixer sset "Speaker Playback Off", "All off"

2. Playback a Sound
# aplay -c 1 -r 16000 -f S16_LE Kalimba.snd
  -c : the number of Channels
  -r : sampling Rate in Hertz
  -f : sample Format (S16_LE = Signed 16bit Little-Endian)

3. Control the volume
# amixer sset "Playback" 255,0

@ Refrence
man 1 aplay