What does “side four” mean?

Question

I recently saw this sentence by Lou Reed:

Anyone who gets to side four is dumber than I am.

On Flavorwire: "The Funniest and Meanest Things Bands Have Said About Their Fans"

What does "side four" mean? Is it an idiom?

Answer 1

Lou Reed's Metal Machine Music is a famously unlistenable album: "generally considered to be either a joke, a grudging fulfilment of a contractual obligation".
There are four 15+ minute long tracks each on one side of vinyl. So "side four" here would be the last track.
He's saying you have to be dumb to listen to it all the way through.

Answer 2

Metal Machine Music was issued was originally issued as a double-LP, so "side four" was actually the second side of the second record. If you listened to the offering from beginning to end, you'd get to side four only after suffering through three previous sides of tape-loop experiments and aimless knob twiddling. The previous commenter's summation—"He's saying you have to be dumb to listen to it all the way through"—is exactly right.

I saw this quote (or one very much like it) in Creem magazine soon after MMM appeared. As I recall, it appeared in a review/interview conducted by Lester Bangs, who was especially unhappy that Lou Reed (whose music he loved) had released such a piece of unlistenable junk immediately after winning a degree of favorable public attention with the brilliant album Transformer (which has "Take a Walk on the Wild Side," "Satellite of Love," and other great songs on it). Bangs thought that Reed was acting out of self-destructive contempt for his fans and for the record-buying public in general.

I remember especially Bangs's resort to capital letters in his article as he wrote something like "Lou finally has a chance to reach a much wider audience with his music—AND HE'S BLOWING IT!" When Bangs confronted Reed in the interview about what a pathetic joke MMM was, Lou said something like "Well at least I'm not stupid enough to listen to it." I don't know whether this was the same quotation cited in the original post here, or whether Reed made essentially the same remark on multiple occasions.