Hey, sorry for delay! Glad to know optimized assets improve performance :D I asked if you were a Linux user, because they often provide great feedback about specific things, and your first post was similar. Looks like I wasn't wrong about your technical knowledge!
We've been making games for quite a while, but mixing of sounds is something we should investigate further. For some reason we don't yet know, some sounds are louder than others. This is regardless of sample volume. I believe it might something to do with frequencies, sample rate or something. A quick & dirty hack we do, is to reproduce the same sound twice, so it gets louder. For example, in this game, armor_break1.ogg - armor_break2.ogg sounds. This doesn't always work. However, the library we use, automatically decreases music volume when other sfx is playing, so that's good. So, yeah, we have volume issues. If you happen to know why, it would be insanely helpful!
Oh, so, you mean, that if the sample doesn't have stereo information, then it should be mono, right?
Thanks for your feedback again <3