[pulseaudio-discuss] how to map equalizer to arbitrary device

Alexander E. Patrakov patrakov at gmail.com
Wed Feb 12 19:19:04 CET 2014

12.02.2014 22:52, Malte Gell wrote:
> Hi there,
> I have enabled the pulseaudio EQ, this gives me 2 new output devices:
> FFT based equalizer on Internal Audio Analog Stereo
> LADSPA Plugin Multiband EQ on Internal Audio Analog Stereo
> I would like to use the EQ with my bluetooth headphone, so how do I map
> the EQ to the bluetooth device? I would like to have a output device
> named like "FFT based equlizer on Philips SHB9100", how do I get it?

Please ignore the "FFT based equalizer". Or better, don't load 
module-equalizer-sink (the module it comes from). It is too bad, both 
from the DSP viewpoint and from the general C coding viewpoint.

The other output device comes from module-ladspa-sink. There are two 
ways to deal with it.

1. As you have obviously followed some instruction to get to the stage 
where it actually creates a sink, please find the instruction again. It 
says either "pacmd load-module module-ladspa-sink lots-of-magic" or "add 
the equivalent load-module directive to default.pa". Now, with "pacmd 
list-sinks | grep name" find the dotted notation for your bluetooth 
device's sink name. Add master=that.dotted.name to the module arguments 
in the instruction.

2. Undo everything that you have done to get these sinks. Install 
veromix (either in the python3 + gtk3 form, or as a KDE plasmoid). Use 
it to attach the equalizer to the bluetooth sink. It will automatically 
load module-ladspa-sink with the correct arguments.

Of course, the master=... approach works with module-equalizer-sink too, 
but I still recommend that you avoid loading that module.

Alexander E. Patrakov

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