“What is bad music?” you ask? Bad Music can be any sound that, when you hear it, makes you think, “That's awful! I have to hear that again!” It's the audio equivalent of “Eeewww!! Smell this!”
There are 3 types of bad music. Intentionally bad music is usually attempting to mock other bad music that some people with no taste are fooled into thinking is good music. Unintentionally bad music is usually an attempt at good music made by someone with little or no talent. And some music, well, we're Not Sure if the “artist” is serious or not.
Bad music comes in all genres - from the intentionally bad classical music of Peter Schickele's “PDQ Bach”, to the mysteriously offkey rapping of Biz Markie to the completely serious horror of Paul Anka. No form of music is safe.
But bad music is easy to recognize no matter what form it comes in. Any time you hear anything that makes the hair on the back of your neck stand up, you're listening to bad music.