Decibel Levels for Storm Medusa 5.1 USB Headset

Decibel Levels for Storm Medusa 5.1 USB Headset

[Alexander Blinne]

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Hello everyone,

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

works fine. Level 0 is mute, hence -infinity dB.

Greetings


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Re: Decibel Levels for Storm Medusa 5.1 USB Headset

[Takashi Iwai]

At Mon, 22 Jul 2013 22:05:14 +0200,
Alexander Blinne wrote:
> 
> Hello everyone,
> 
> 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?


Takashi

> 
> works fine. Level 0 is mute, hence -infinity dB.
> 
> Greetings
> 

Re: Decibel Levels for Storm Medusa 5.1 USB Headset

[Alexander Blinne]

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Hello,

well I have to admit that those level were just a guess. I have now made
an accurate measurement of the real volume levels by playing back white
noise through the headset and recording with a microphone at the same
time, while increasing the hardware volume level with 'amixer'. Then i
have measured the volumes with audacity's contrast-analyzer and smoothed
the resulting curve by applying a nonlinear least squares fit with a
function a*log(x+d*x^2+e*x^3)+b+c*x, wich fits the data really well.

The resulting levels are:

0	invalid/unconclusive, sometimes mute, sometimes louder than 1. seems
not to be working correctly.

1	-24,91
2	-22,31
3	-20,10
4	-18,15
5	-16,46
6	-15,00
7	-13,73
8	-12,61
9	-11,62
10	-10,72
11	-9,91
12	-9,17
13	-8,49
14	-7,87
15	-7,28
16	-6,74
17	-6,23
18	-5,75
19	-5,30
20	-4,88
21	-4,48
22	-4,09
23	-3,73
24	-3,38
25	-3,05
26	-2,74
27	-2,44
28	-2,15
29	-1,87
30	-1,61
31	-1,35
32	-1,10
33	-0,87
34	-0,64
35	-0,42
36	-0,21
37	0,00


Alex



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Re: Decibel Levels for Storm Medusa 5.1 USB Headset

[Raymond Yau]

> >
> > 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.html

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
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Re: Decibel Levels for Storm Medusa 5.1 USB Headset

[Raymond Yau]

> >>> 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.html
> >
> > 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.html

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
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