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

Lennart Poettering mznyfn at 0pointer.de
Mon Apr 14 19:00:24 CEST 2008

On Sat, 12.04.08 21:32, Rene Herman (rene.herman at keyaccess.nl) wrote:

> On 12-04-08 15:35, Lennart Poettering wrote:
> > On Sat, 12.04.08 12:15, James Courtier-Dutton (James at superbug.co.uk) wrote:
> > 
> > My I thus assume that we can say that for all but the last element in
> > the series 0db means avg input power equals avg output power, and for
> > the last one 0db means max? That would fit on what you are saying but
> > also match my usb speakers, not depending on the existance of a
> > "Master".
> 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?


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

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