[pulseaudio-discuss] Delayed muting of studio speakers

Chris Mayes cmayes at cmayes.com
Sat Dec 19 21:23:06 UTC 2020

Oh well, the auto-mute didn't help.  The pulse logs don't show anything,

(base) cmayes at ninja:/home/cmayes $ sudo journalctl -u pulseaudio.service
-- Logs begin at Wed 2020-12-16 09:16:17 MST, end at Sat 2020-12-19
14:18:08 MST. --
-- No entries --

This time it was a quiet song (Iron & Wine's cover of Waitin' for a
Superman), so that may be a factor.

Maybe I need a pre-amp?  I'll contact the speaker people to see whether
they have any ideas.



On Sat, Dec 19, 2020 at 2:04 PM Chris Mayes <cmayes at cmayes.com> wrote:

> Oh, I didn't realize that pulse was built upon Alsa.  I pulled up
> alsamixer and found an "auto-mute" option that was binary but listed as a
> fader on the display.  I've disabled it; maybe that'll help.
> From what I've skimmed, it looks like this is to account for, say, a
> headphone jack being plugged in.  I rarely do this (almost always
> Bluetooth), so switching off this detection is low-risk.  Bluetooth might
> not trigger the switch, but I can always just switch off the main speakers.
> Thanks for the lead!  I'll send an update if/when this solves the issue.
> Thanks!
> -Chris
> On Sat, Dec 19, 2020 at 1:20 PM Matt Feifarek <matt.feifarek at gmail.com>
> wrote:
>> 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
>>> _______________________________________________
>>> pulseaudio-discuss mailing list
>>> pulseaudio-discuss at lists.freedesktop.org
>>> https://lists.freedesktop.org/mailman/listinfo/pulseaudio-discuss
>> _______________________________________________
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