tuedel@tuedel-o-mat:~$ speaker-test -c2 -Ddefault -twav

speaker-test 1.0.14rc2

Playback device is default
Stream parameters are 48000Hz, S16_LE, 2 channels
WAV file(s)
Broken configuration for playback: no configurations available: Invalid argument
Setting of hwparams failed: Invalid argument
tuedel@tuedel-o-mat:~$ speaker-test -c2 -Dch51dup -twav

speaker-test 1.0.14rc2

Playback device is ch51dup
Stream parameters are 48000Hz, S16_LE, 2 channels
WAV file(s)
Broken configuration for playback: no configurations available: Invalid argument
Setting of hwparams failed: Invalid argument