On Tue, 16.02.10 14:40, Mark Brown (broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx) wrote: > > On Tue, Feb 16, 2010 at 03:32:01PM +0100, Lennart Poettering wrote: > > On Tue, 16.02.10 09:24, Jaroslav Kysela (perex@xxxxxxxx) wrote: > > > > Line: 0dB..47.81dB # seems correct -47.81dB..0dB > > > Line Capture: -0.18dB..23.81dB # seems correct > > > -17.81dB..6.18dB > > > Hmm, how did you choose where to put 0dB? > > The Line one looks like someone got attenuation and gain confused, which > is a fairly common mistake for people to make when copying information > from one place to another. Possibly a similar thing going on with the > Line Capture control, plus a fixed 6dB gain (which may well be a > separate amp...). I remember that a while back we had a discussion on alsa-devel regarding the fact that ALSA does not define relative to what the dB values reported by the mixer elements actually are measured. Some mixer controls export dB values relative to max amplification (e.g. my integrated USB speakers here), others relative to the output of some other mixer element, and others relative to different standard or not-so-standard output voltages. And there is no API to figure out what the base is. Now, what Jaroslav listed above suggests that he chose carefully where he put 0dB. I was just wondering about that. Jaroslav, how did you choose where to put 0dB? Lennart -- Lennart Poettering Red Hat, Inc. lennart [at] poettering [dot] net http://0pointer.net/lennart/ GnuPG 0x1A015CC4 _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
