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)
ALSA lib pcm.c:2145:(snd_pcm_open_noupdate) Unknown PCM ch51dup
Playback open error: -2,No such file or directory
ALSA lib pcm.c:2145:(snd_pcm_open_noupdate) Unknown PCM ch51dup
Playback open error: -2,No such file or directory
ALSA lib pcm.c:2145:(snd_pcm_open_noupdate) Unknown PCM ch51dup
Playback open error: -2,No such file or directory
ALSA lib pcm.c:2145:(snd_pcm_open_noupdate) Unknown PCM ch51dup
Playback open error: -2,No such file or directory

tuedel@tuedel-o-mat:~$ speaker-test -c2 -Dplug:ch51dup -twav

speaker-test 1.0.14rc2

Playback device is plug:ch51dup
Stream parameters are 48000Hz, S16_LE, 2 channels
WAV file(s)
ALSA lib pcm.c:2145:(snd_pcm_open_noupdate) Unknown PCM ch51dup
Playback open error: -2,No such file or directory
ALSA lib pcm.c:2145:(snd_pcm_open_noupdate) Unknown PCM ch51dup
Playback open error: -2,No such file or directory
ALSA lib pcm.c:2145:(snd_pcm_open_noupdate) Unknown PCM ch51dup
Playback open error: -2,No such file or directory

tuedel@tuedel-o-mat:~$ speaker-test -c6 -Dplug:dmix6 -twav

speaker-test 1.0.14rc2

Playback device is plug:dmix6
Stream parameters are 48000Hz, S16_LE, 6 channels
WAV file(s)
Rate set to 48000Hz (requested 48000Hz)
Buffer size range from 2048 to 5120
Period size range from 1024 to 1024
Using max buffer size 5120
Periods = 4
was set period_size = 1024
was set buffer_size = 5120
 0 - Front Left
 4 - Center
 1 - Front Right
 3 - Rear Right
 2 - Rear Left
 5 - LFE

tuedel@tuedel-o-mat:~$ speaker-test -c6 -Ddmix6 -twav

speaker-test 1.0.14rc2

Playback device is dmix6
Stream parameters are 48000Hz, S16_LE, 6 channels
WAV file(s)
Sample format not available for playback: Invalid argument
Setting of hwparams failed: Invalid argument