2010/2/17 Lennart Poettering <mznyfn@xxxxxxxxxxx> > On Tue, 16.02.10 23:38, Mark Brown (broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx) > wrote: > > > > > On Tue, Feb 16, 2010 at 11:42:12PM +0100, Lennart Poettering wrote: > > > On Tue, 16.02.10 22:39, Mark Brown ( > broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx) wrote: > > > > > > Typically the DACs and ADCs will have a full scale signal at line > > > > reference level - it should generally be a good approximation with > > > > nothing else to go on. > > > > > "line reference level"? What is that? > > > > As I understand it (and bear in mind that I'm a software rather than > > electrical engineer) it's not 100% fixed, though since the actual result > > depends very much on what it's connected to an absolute answer isn't as > > important as it might be. 1V RMS is very standard in consumer stuff at > > least. > > > > If you could frame exactly the information that you're looking for then > > I should be able to ask a few people who are electrical engineers and > > get a more coherent answer for you. I guess you're looking at trying > > to have PulseAudio set sensible levels by default? > > Nah. I actually don't need this value for PulseAudio. In PulseAudio I > chose to shift all scales so that maximum amplification becomes 0 dB, > so that the UIs are similar to how most hifi racks do it, and which I > think is a nice, easy and understandable logic. That way my volume > scales range from -inf dB to 0 dB in all cases, regardless of the > hardware/drivers in use. Of course, that means that ALSA's own 0dB is > not directly visible on the scale. Because it might be sometimes > useful to know where it is, we export that position as "base volume" > and the UIs show it with a little marker at the side. > > The reason I was asking how Jaroslav chose the 0dB position for his > measurements was purely because I wanted to do my own measurements for > that Aureon card. The dbmeasure tool I wrote for stuff like that puts > 0dB at max amplification, however Jaroslav didn't, so I was wondering > how he chose 0dB then. > > Lennart > > From the viewpoint of user, they only care how easy to find the point which is no software gain or software auttentation since software gain lead to clipping _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
