I hope this Information helps. I have the Storm Medusa 5.1 USB Headset which reports wrong decibel levels to pulseaudio. My Alsa-Info are located at
http://www.alsa-project.org/db/?f=a882f3db6769c5dfce83c266946eff52d1d55349
The Headset is card2 in the above dump.
My decibel levels-fix
[DecibelFix Speaker] db-values = 1:-30 37:3
How did you define these values?
http://mailman.alsa-project.org/pipermail/alsa-devel/2007-November/003867.ht...
If your headset have windows driver, need to find out which USB chip and look at the datasheet of the chip
e.g. cm106l ’s datasheet contain a table of dac volume cortol
Ok looks like cm6206 is only in newer versions of the headset in older (like mine) there is cm106l , maybe there are other chips as well but i don't know.
http://mailman.alsa-project.org/pipermail/alsa-devel/2007-November/003877.ht...
Seem same USB audio id
idVendor 0x0d8c C-Media Electronics, Inc. idProduct 0x0006
Do you find out the audio chip from product spec, user manual or windows driver ?
Master volume control by default; per-channel volume control by C-Media driver
Refer to the function block diagram , dac with volume controls 0 to -45dB
There is a table of dac volume control in linear scale