I don't know what it's from, though. A battle tune with a short loop (it's less than ten seconds long), or a section of a song I happen to be looping in my head without the ability to know what comes before or after.
I do know it's there, though. It's made up of two electric guitars, one bass and the other also fairly deep.
It's approximately six measures long by my very rough estimate, and goes something like this for the main part:
Bah, da(u) duh(d)-duh(u?) da(u)-da(u?), Da(u) duh(d)-duh(u?) da(u)-da(u?), Da(u) duh(d)-duh(u?) da(u)-da(u?), Da(u) duh(d)-duh(u?) da(u)-da(u?)-duh(d)-duh(u?),
And then repeating.
The bass supports that, as, Dah-dah, duh-dah-dah, duh-dah-dah, duh-dah-dah-da-da, with that taking up the same amount of time as the above, overlayed so that the notes more or less match.
It's a really good tune. I just wish I knew where it was from.