dans amixer output

Simple mixer control 'Master',0
  Capabilities: pvolume pswitch
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 43
  Mono:
  Front Left: Playback 20 [47%] [on]
  Front Right: Playback 20 [47%] [on]
Simple mixer control 'PCM',0
  Capabilities: pvolume
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 255
  Mono:
  Front Left: Playback 246 [96%]
  Front Right: Playback 246 [96%]
Simple mixer control 'Front Mic',0
  Capabilities: cswitch cswitch-joined cswitch-exclusive
  Capture exclusive group: 0
  Capture channels: Mono
  Mono: Capture [on]
Simple mixer control 'Mic',0
  Capabilities: cswitch cswitch-joined cswitch-exclusive
  Capture exclusive group: 0
  Capture channels: Mono
  Mono: Capture [off]
Simple mixer control 'Capture',0
  Capabilities: cvolume cswitch
  Capture channels: Front Left - Front Right
  Limits: Capture 0 - 23
  Front Left: Capture 21 [91%] [on]
  Front Right: Capture 21 [91%] [on]