USB Audio Volume Too High

[Charles W. Ross]

Hi everyone,

I have a cheap, generic USB sound card (pcm2 on my system) that is
giving me trouble on FreeBSD 10.3. 

It works just fine, except for the fact that the audio output seems to
be at the maximum level (way too high), and I can't seem to adjust it.
(I know the card itself is OK because it works normally in Linux). Below
I've included some relevant output.

My current 'mixer' output:

cwr at nuc:~ % mixer
Mixer vol      is currently set to   0:0
Mixer pcm      is currently set to   0:0
Mixer mic      is currently set to   0:0

And yet, the output of the device is full-blast.

Here are all the relevant sysctls:

cwr at nuc:~ % sysctl -a | grep pcm.2
dev.pcm.2.feedback_rate: 0
dev.pcm.2.mixer.mute_3.desc: 
dev.pcm.2.mixer.mute_3.max: 1
dev.pcm.2.mixer.mute_3.min: 0
dev.pcm.2.mixer.mute_3.val: 0
dev.pcm.2.mixer.vol_2.desc: 
dev.pcm.2.mixer.vol_2.max: 6096
dev.pcm.2.mixer.vol_2.min: 794
dev.pcm.2.mixer.vol_2.val: 0
dev.pcm.2.mixer.mute_1.desc: USB  AUDIO  
dev.pcm.2.mixer.mute_1.max: 1
dev.pcm.2.mixer.mute_1.min: 0
dev.pcm.2.mixer.mute_1.val: 0
dev.pcm.2.mixer.vol_0_1.desc: USB  AUDIO  
dev.pcm.2.mixer.vol_0_1.max: 17152
dev.pcm.2.mixer.vol_0_1.min: 0
dev.pcm.2.mixer.vol_0_1.val: 0
dev.pcm.2.mixer.vol_0_0.desc: USB  AUDIO  
dev.pcm.2.mixer.vol_0_0.max: 17152
dev.pcm.2.mixer.vol_0_0.min: 0
dev.pcm.2.mixer.vol_0_0.val: 0
dev.pcm.2.bitperfect: 0
dev.pcm.2.buffersize: 0
dev.pcm.2.rec.vchanformat: s16le:2.0
dev.pcm.2.rec.vchanrate: 24000
dev.pcm.2.rec.vchanmode: fixed
dev.pcm.2.rec.vchans: 1
dev.pcm.2.play.vchanformat: s16le:2.0
dev.pcm.2.play.vchanrate: 48000
dev.pcm.2.play.vchanmode: fixed
dev.pcm.2.play.vchans: 2
dev.pcm.2.hwvol_mixer: vol
dev.pcm.2.hwvol_step: 5
dev.pcm.2.%parent: uaudio0
dev.pcm.2.%pnpinfo: 
dev.pcm.2.%location: 
dev.pcm.2.%driver: pcm
dev.pcm.2.%desc: USB audio

And finally /dev/sndstat:

cwr at nuc:~ % cat /dev/sndstat 
Installed devices:
pcm0: <Intel Panther Point (HDMI/DP 8ch)> (play)
pcm1: <Intel Panther Point (HDMI/DP 8ch)> (play)
pcm2: <USB audio> (play/rec) default

Any help to adjust the output level of this device would be greatly
appreciated!

Thanks,

Charlie