conn@inspiron:~$ speaker-test -c2 -Dplug:equalized -twav

speaker-test 1.0.14

Playback device is plug:equalized
Stream parameters are 48000Hz, S16_LE, 2 channels
WAV file(s)
ALSA lib pcm_params.c:2152:(snd_pcm_hw_refine_slave) Slave PCM not usable
Broken configuration for playback: no configurations available: Invalid argument
Setting of hwparams failed: Invalid argument