cat /proc/asound/devices

livingdaylight@gooseberry:~$ cat /proc/asound/devices
  1:        : sequencer
  2: [ 0- 3]: digital audio playback
  3: [ 0- 1]: digital audio playback
  4: [ 0- 0]: digital audio playback
  5: [ 0- 0]: digital audio capture
  6: [ 0- 3]: hardware dependent
  7: [ 0- 0]: hardware dependent
  8: [ 0]   : control
 33:        : timer
livingdaylight@gooseberry:~$