[pulseaudio-discuss] Equalizer setting is forgotten until PA is restarted and sound stutters

Zsolt Szakács szakacs.zsolt at zoho.com
Wed Jul 9 06:54:43 PDT 2014

On 2014-07-08 12:40, Jason Newton wrote:
> On Mon, Jul 7, 2014 at 8:47 AM, Zsolt Szakácswrote:
>     Hello,
>     I'm using the equalizer sink for PulseAudio 4.0 under SolydK so
>     that my subwoofer emits sound only about 80 Hz and below in my 5.1
>     sound system. (I wanted to try another solution to do this, as I
>     wrote in my post on Stackexchange here
>     <http://unix.stackexchange.com/questions/138810/low-pass-filter-on-lfe-using-pulseaudio>,
>     but it wasn't successful.) Also, I'm using gstreamer.
>     One problem is that every time I reboot, the settings in qpaeq
>     don't seem to take effect. Even if I open qpaeq and start moving
>     the scales, the change is not reflected in the sound at all.
>     However, if I enter /pulseaudio -k/ and then /pulseaudio -D/ in
>     the terminal, I can hear that equalization is applied.
> Hi,
> Re the equalizer, this sounds very odd, perhaps somehow one of the 
> modules is not loaded when your desktop environment starts pulse?  
> Could you try using pacmd list-modules and look for 
> module-dbus-protocol and module-equalizer-sink on such conditions?  
> Are you sure applications are being routed through the equalizer? A 
> good way to check is pavucontrol.
>     Another problem is that when the equalized sink is the default
>     sink, sound stutters when watching a video on YouTube with Firefox
>     and Flash or playing an mp3 with VLC. However, there is stuttering
>     only at the beginning or the end of playing (when I select stop)
>     or jumping to a particular position while playing a video in
>     SMplayer, Mplayer, VLC, or listening to music in Clementine.
> These are buffering issues manifesting with flash and others with 
> events causing a rewind (start/stop/seek) when multiple sources are 
> active - my advice for now is to not use flash and the equalizer 
> together and instead have flash content go directly to the device 
> sink. The rewind issues on multiple sources is another long standing 
> issue to fix but if you do not have multiple sources active, it will 
> not manifest. For what its worth, they are problems I want to look 
> into to characterize better and fix but I am months out from having 
> the luxury of time to do it.
> Regards,
> -Jason
> _______________________________________________
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> pulseaudio-discuss at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/pulseaudio-discuss
Hi Jason,

I've checked the loaded modules and both before and after restarting PA 
both module-dbus-protocol and module-equalizer-sink are loaded. However, 
I also noticed that a few modules are not loaded again after restarting 
PA, namely /module-device-manager//, module-x11-publish, 
//module-x11-cork-request/, and /module-x11-xsmp/.

I've also checked pavucontrol (thanks for mentioning it), and it looks 
like the equalized sink doesn't get any signal until I switch the output 
in the playback tab (but then it reverts back to the unequalized 5.1 
sink after playing another audio or video file) or I restart PA from 

Also, as for the issue with Flash, interestingly, if I switch to the 
equalized sink inside pavucontrol, there is no stuttering apart from for 
a short time after I switch, but, again, this is a temporary solution.

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