LSD + MDMA taken together can also distort your hearing. Some time after ingesting this mixture at a party, I heard an extremely strange sound, like something out of a synthesizer. I asked some other people (some sober, drunk, etc) what that sound was and they all agreed it was a completely normal sounding ambulance siren. I didn't believe it so I recorded a video to listen to the next day, and it was indeed just a normal siren.

I'd be interested in seeing the experiments they did with the two subjects with perfect pitch. For them, it must be very disorienting, but also quite interesting.