bobby@bobby-ubuntu:~$ speaker-test -Dplug:surround51 -c6
speaker-test 1.0.13
Playback device is plug:surround51
Stream parameters are 48000Hz, S16_LE, 6 channels
Using 16 octaves of pink noise
ALSA lib confmisc.c:1105:(snd_func_refer) Unable to find definition 'defaults.pcm.surround51.card'
ALSA lib conf.c:3500:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory
ALSA lib confmisc.c:242:(snd_func_getenv) error evaluating default
ALSA lib conf.c:3500:(_snd_config_evaluate) function snd_func_getenv returned error: No such file or directory
ALSA lib conf.c:3957:(snd_config_expand) Args evaluate error: No such file or directory
ALSA lib pcm.c:2143:(snd_pcm_open_noupdate) Unknown PCM surround51
Playback open error: -2,No such file or directory
bobby@bobby-ubuntu:~$