How did Lou Reed create Metal Machine Music.

All I've heard is that he manoipulated guitar feedback with amps in a room. I can't imagine you could make some of the sounds I'm hearing from that alone - how did he do it? Tape manipulation? Delay oscillation? Nothing sounds familiar, like I'm in some other dimension of music.

My brain seems to be becoming almost apophenic and noticing voices and melodies in the music that simply aren't as it tries desperately to derive some meaning from the chaos of sound.

Almost psychedelic