This is a bit of a mysterious issue to me. I haven't found any of the speaker boost programs that work for my N7. Yet, the Mx video player has a speaker boost mode and that function REALLY works. I can get at least twice the normal max volume with Mx player.. enough to nearly melt the speaker right out of the case
That being said, I can't figure out why there don't seem to be any stand-alone speaker boost programs that work. Mx Player clearly demonstrates it can be done. I'm rooted, by the way, and on the latest stock JB and kernel... 4.2.1.