Hissing noise introduced, when using alsaloudness after equalization about alsaloudness HOT 2 CLOSED

I need to do more research. If this is still an issue I'll reopen.

from alsaloudness.

One thing I can tell you, is that the loudness compensation carried out by alsaloudness is essentially done via boosting of the bass and treble content and this boosting intensified as the attenuation goes up (or down in terms of negative dB - see the curves published in the README). So, although it might well be conceivable, that the filtering done by alsaloudness introduces the hissing artifact, it is also likely that it either makes a hiss in the source material more pronounced (I haven't noticed anything of the kind with any of the material I listen to), or that the boosted content causes the equalization plugin (which you seem to have placed downstream of alsaloudness) to misbehave, producing the hiss.

This suggests a few things to try:

1. Temporarily remove the REW plugin, to take it out of the picture and see if the hiss is still there.
2. Try different source material, preferably from different labels and genres, trying to find if the hiss is (at least in part) due to the material, or not.
3. Try to reverse the order of chaining, so that alsaloudness is at the end, right before the HW PCM.
4. Try different equalization plugins.

from alsaloudness.