[alsa-devel] Decibel Levels for Storm Medusa 5.1 USB Headset

[Alexander Blinne]

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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