[alsa-devel] wrong decibel data?

Raymond Yau superquad.vortex2 at gmail.com
Thu Apr 8 04:05:28 CEST 2010

2010/4/6 Nicolo' Chieffo <nicolo.chieffo at gmail.com>

> I've already attached my alsa-info.log in my first post.
> * alsamixer 0 dB (100%):
> Simple mixer control 'Master',0
>  Capabilities: pvolume pswitch pswitch-joined penum
>  Playback channels: Front Left - Front Right
>  Limits: Playback 0 - 65536
>  Mono:
>  Front Left: Playback 64044 [98%] [on]
>  Front Right: Playback 64044 [98%] [on]

Most users only care about 0dB point since any software gain is the cause of
clipping (distortion) when the volume control provide software gain


In digital signal
clipping occurs when the signal is restricted by the range of a chosen
representation. For example in a system using 16-bit
32767 is the largest positive value that can be represented, and
if during processing the amplitude of the signal is doubled,
sample<http://en.wikipedia.org/wiki/Sample_%28signal%29>values of
32000 should become 64000, but instead they are truncated to the
maximum, 32767.

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