Ubuntu – adjust max possible volume in pulseaudio


Somtimes some sound/movie/music on my Ubuntu_12.04 system is at a very low volume by itself.
Henceforth I increase the volume of the sound output. I can use the following setting (see screenshot)
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It seems therefore that pulseaudio is able to increase the volume beyond the maximum that appears possible by merely using the "increase-volume" buttons of the machine.
My questions is how I can adjust Pulseaudio to allow a greater range or a higher max volume increasing???

Especially with some audio material that is at a very low volume to start with it would be nice to be able to swiftly increase the output volume (powerup) to a higher setting than maybe necessary to other -already quite loud- material.

Best Answer

The maximal possible volume level we can obtain from sliding the volume control to more than 100% is approx. 153% above the normal peak limit. Provided we had set the ALSA volume with alsamixer to 100 these 100% are the level above which audio will be clipped or distorted. This also will happen when amplifying to 153% with the slider.

Nevertheless is is possible to further increase this level by setting the sink level using the follwing command in a terminal:

pacmd set-sink-volume <sink> <value>

Replace <sink> with your sink name or sink index as given from:

pacmd list-sinks

The lower limit for <value> obviously is 0, a linear volume of 100% is a value of 65536, anything higher will be further amplified. A value of 512000 will thus lead to an overamplification of 781%.

This is a very crude method to amplify sound output of varying level as overamplifying will lead not only to clipping and ugly distortion but may also damage your speakers.

Therefore it would be a better way to normalize your audio output. See the following question on how to do this with pulseaudio: