amixer mute/unmute не работают

amixer -c 0 set Master mute
amixer: Invalid command!

Какой синтаксис правильный?

amixer -c 0
Simple mixer control 'Master',0
Capabilities: pvolume cvolume
Playback channels: Front Left - Front Right
Capture channels: Front Left - Front Right
Limits: Playback 0 - 256 Capture 0 - 256
Front Left: Playback 34 [13%] [-55.50dB] Capture 34 [13%] [-55.50dB]
Front Right: Playback 34 [13%] [-55.50dB] Capture 34 [13%] [-55.50dB]

При этом amixer -c 0 set Master <число> звук меняет.