[alsa-devel] What does 0dB refer to? (Logitech USB Speakers)

Lennart Poettering mznyfn at 0pointer.de
Mon Apr 14 19:28:39 CEST 2008

On Mon, 14.04.08 19:22, Rene Herman (rene.herman at keyaccess.nl) wrote:

> On 14-04-08 19:00, Lennart Poettering wrote:
> > On Sat, 12.04.08 21:32, Rene Herman (rene.herman at keyaccess.nl) wrote:
> >> If we add in ISA cards, it's not a very generic assumption at least. For 
> >> example on my cs4236, "master" is -94,5 to +12 dB with 0dB at "87" in the 
> >> integer scale.
> >>
> >> It's a "Master Digital Gain" -- not sure what that "digital" implies as it 
> >> very much seems to be positioend in the post output mixer analog path...
> > 
> > Maybe the driver should add an internal offset to the dB scale, to
> > guarantee that 0dB is max, instead of just copying the hw specs?
> No, really quite definitely not. 0 dB means no attenuation of amplification. 
> How loud that actually ends up is very much dependent on what's _behind_ 
> your line-out.

Yes, but what I am asking for is to define the dB values of the master
control relative to the some ref level on this line-out. What happens
after the line-out doesn't matter at all.


Lennart Poettering                        Red Hat, Inc.
lennart [at] poettering [dot] net         ICQ# 11060553
http://0pointer.net/lennart/           GnuPG 0x1A015CC4

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