load-module module-echo-cancel aec_args="analog_gain_control=0 digital_gain_control=0"
+
in the file:
/etc/pulse/daemon.conf
or
~/.config/pulse/daemon.conf
Uncomment the line, and set to no:
flat-volumes = no
A. Panagiotidis, S. Frey, and T. Ertl. Eurographics Conference on Visualization (EuroVis) - Short Papers, page 13-17. The Eurographics Association, (2015)
T. Ropinski, F. Steinicke, and K. Hinrichs. Journal Proceedings of the 14th International Conference in Central Europe on Computer Graphics, Visualization and Computer Vision (WSCG06), (2006)