Correct, it's now muted. Now you need to try different settings of the 'IEC958 Playback AC97-SPSA' element,
e.g., amixer set 'IEC958 Playback AC97-SPSA' 1
or
amixer set 'IEC958 Playback AC97-SPSA' 2
amixer set 'IEC958 Playback AC97-SPSA' 3
Correct, it's now muted. Now you need to try different settings of the 'IEC958 Playback AC97-SPSA' element,
e.g., amixer set 'IEC958 Playback AC97-SPSA' 1
or
amixer set 'IEC958 Playback AC97-SPSA' 2
or
amixer set 'IEC958 Playback AC97-SPSA' 3