[pulseaudio-discuss] Delayed muting of studio speakers

[Matt Feifarek]

I'm not following everything that you're writing (including the file you
mentioned... which I've never messed with, but I find on my system
as /usr/share/pulseaudio/alsa-mixer/paths/analog-output.conf.common)

I think, though, that the file you mention might have to do with the alsa
mixer labels in the ui of the console "alsamixer" program more than the
lower level wiring, but I'm not sure. There are lots of dark arts in the
alsa. Personally, I wouldn't mess with that stuff.

When the speakers drop out, is there anything in your logs? You can check
with:
sudo journalctl -u pulseaudio.service

Are you certain that the software is muting, and it's not just some kind of
dropout?

The system can't see what kind of speakers you have, since they're hooked
up via analog line out. I doubt that impedance is an issue, but I'm not
very familiar with the analog side of things.

If you're just using line out, PA should be fine, and you shouldn't have to
worry about detecting, auto-detecting, or the like. Playing analog out
through onboard sound is pretty normal, you shouldn't be having any
trouble... but see what's in your logs.




On Sat, Dec 19, 2020 at 1:43 PM Chris Mayes <cmayes at cmayes.com> wrote:

> Hi, everybody!
>
> It takes me back to have subscribed via Mailman to an email distribution
> list.  I'm generally able to solve my issues via Googling, but this one's
> proven tricky.
>
> I recently bought a pair of KRK Classic 5
> <https://www.krkmusic.com/Classic> speakers to replace a pair of M-Audio
> Studiophile AV 40 <https://m-audio.com/products/view/studiophile-av-40>
> speakers that had developed a rapid popping noise in the internal
> amplifier.  The new speakers sound fantastic, but they have an odd
> spontaneous muting issue, at least as configured.
>
> The issue is that the speakers seem to become muted (first one, then the
> other, usually L->R) after some time of playing without any issues.  My
> provisional solution is to crank the volume past 100%, which un-mutes them
> (though at an unpleasantly loud volume).  This clears up the issue, though
> it usually happens again a few minutes later once I've brought the volume
> back to a reasonable level.
>
> Based on my Googling, I tried modifying analog-output.conf.common to
> "ignore" volume.  Here's the PCM block:
>
> [Element PCM]
> switch = on
> volume = ignore
> volume-limit = 2.0
> override-map.1 = all
> override-map.2 = all-left,all-right
>
> Sadly, this didn't seem to make any difference.  What else might I try?
>
> I have a passing familiarity with audio concepts, and one difference that
> I noted is that the new speakers have about half of the impedance of the
> old pair (which never had this problem).  Do sound cards use impedance to
> detect the presence of a device?  It's plugged into line-out (lime green)
> on an Asus Xonar SE <https://www.asus.com/us/Sound-Cards/Xonar-SE/> (the
> motherboard (Asus PRIME Z390-A)
> <https://www.asus.com/us/Motherboards/PRIME-Z390-A/> had the same issue).
>
> Also, the audio is fed to each speaker separately rather than being fed to
> a single speaker and bridged to the left via speaker cable.  Maybe that's a
> factor?
>
> The brute-force thing would be to just mark the line-out port as "always
> on" and to skip attempts to detect whether there's a device connected.  Can
> PulseAudio do this?  More elegant solutions are also warmly welcomed.
>
> Thanks,
>
> -Chris Mayes
>
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