On Sun, Jan 29, 2012 at 11:04 PM, Ralf Mardorf <ralf.mardorf@alice-dsl.net> wrote:
Since the sound device is ok when using ALSA only, the +4dBu vs -10dBV information or any ratio dB to fader position or what ever you mean, must be somewhere provided correctly by ALSA. If such a dB issue should be the cause, than I suspect PA pulls this information from the wrong place. What happens, when using Arts or any other sound server?
ALSA is not using this information in the same way (if at all). It is a well known problem that PA will act crazy if the dB values from ALSA are wrong, but ALSA itself mostly does not care (because the user is setting all the mixer level themselves, unlike in PA where there are heuristics doing clever stuff). To learn more, run test and find the correct values that can be reported to ALSA, see: <http://pulseaudio.org/wiki/BadDecibel>.
In case of doubt file a bug report to ALSA and PA.
Sure, but do the test above first. It will save some time.
IIRC the sound device works correctly since years for ALSA, just when using PA there's distortion. Is it reasonable to assume that there's a bug for ALSA?
In this case, this is a well known class of bugs, so yes that's reasonable (but not certain).
Perhaps an user error? If the device should support +4dBu and -10dBV, than the user perhaps missed to choose the correct level. Nor ALSA neither PA does know what equipment is connected to the audio IOs.
The user should not need to know about dB levels when using PA, so this is a software bug (somewhere). -t