A few links to music which sounds as if it were played without any reference to performance traditions.

Of course, The Shaggs are unavoidable. Here’s a page about their
Philosophy of the World (PotW) album.
Two tracks from that album:

My Pal Foot Foot (MP3)
Who Are Parents (MP3)

Also, three DailySonic segments on outsider music. Segment 1 (August 8, 2k5), Segment 2 (August 10, 2k5), Segment 3 (August 12, 2k5).

Those may all be influential. It’s hard not to rethink your idea of music when you listen to any of these. It’s not just about being “the worst music ever played,” as some of these excerpts are claimed to be. It’s about music outside of what people tend to consider “normal” or “acceptable” as music.