So, after all those years occasionally lurking this lovely ol' forum (since around '99), i ended up in need of help finding something.
I assume you guys are experts in this and will shoot down this doubt 'o mine in a minute's notice.
So, i was playing freedoom using the Zandronum port, and heard a Metallica song with no vocals playing on the background while i was blasting imps on Brutal Doom v20, much like the ones found in Doom Metal Vol.4 .wad
Specifically it was Sad But True.
It was likely a custom music .wad i was using, but i can't put a finger on it anymore - tried finding it on google with certain keywords, this and other forums and no result, and i don't have the file anymore, nor know the filename, and since the last copy of it was in the computer of a company i worked for some time ago, it is surely gone in the monthly cleaning.
As additional info, the song sounded way too good to be a .midi table, so all bets on .ogg.
TL;DR: Trying to find instrumental Metallica - Sad but True song that was played on doom, not an ordinary .midi. Suspects being Zandronum, BD v20 or some custom music .wad, ordered from least to most suspect.