[mythtv@mediapc ~]$ speaker-test -c6 -Dplug:surround51 -t wav -l1

speaker-test 1.0.14

Playback device is plug:surround51
Stream parameters are 48000Hz, S16_LE, 6 channels
WAV file(s)
ALSA lib confmisc.c:1286:(snd_func_refer) Unable to find definition 'cards.NFORCE.pcm.surround51.2:CARD=0'
ALSA lib conf.c:3510:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory
ALSA lib conf.c:3982:(snd_config_expand) Evaluate error: No such file or directory
ALSA lib pcm.c:2144:(snd_pcm_open_noupdate) Unknown PCM surround51
Playback open error: -2,No such file or directory
ALSA lib confmisc.c:1286:(snd_func_refer) Unable to find definition 'cards.NFORCE.pcm.surround51.2:CARD=0'
ALSA lib conf.c:3510:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory
ALSA lib conf.c:3982:(snd_config_expand) Evaluate error: No such file or directory
ALSA lib pcm.c:2144:(snd_pcm_open_noupdate) Unknown PCM surround51
Playback open error: -2,No such file or directory
ALSA lib confmisc.c:1286:(snd_func_refer) Unable to find definition 'cards.NFORCE.pcm.surround51.2:CARD=0'
ALSA lib conf.c:3510:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory
ALSA lib conf.c:3982:(snd_config_expand) Evaluate error: No such file or directory
ALSA lib pcm.c:2144:(snd_pcm_open_noupdate) Unknown PCM surround51
Playback open error: -2,No such file or directory
ALSA lib confmisc.c:1286:(snd_func_refer) Unable to find definition 'cards.NFORCE.pcm.surround51.2:CARD=0'
ALSA lib conf.c:3510:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory
ALSA lib conf.c:3982:(snd_config_expand) Evaluate error: No such file or directory
ALSA lib pcm.c:2144:(snd_pcm_open_noupdate) Unknown PCM surround51
Playback open error: -2,No such file or directory