:~$ amixer sset Master toggle Simple mixer control 'Master',0 Capabilities: pvolume pvolume-joined pswitch pswitch-joined penum Playback channels: Mono Limits: Playback 0 - 31 Mono: Playback 16 [52%] [-22.50dB] [off]
this means that ctl.default is not set to ctl.pulse as your master volume still have dB scale but pulseaudio master volume not yet implemented dB scale
:~$ amixer sset Master toggle
Simple mixer control 'Master',0
Capabilities: pvolume pvolume-joined pswitch pswitch-joined penum
Playback channels: Mono
Limits: Playback 0 - 31
Mono: Playback 16 [52%] [-22.50dB] [off]
this means that ctl.default is not set to ctl.pulse as your master volume still have dB scale but pulseaudio master volume not yet implemented dB scale