Am I insane for worrying about this?

Not at all. As I said, the science shoppe investigates this stuff regularly in my country. People who have become diseased and depressed claimed there was something with low sound waves happening, and they were RIGHT. One time, the waves were emenating from the ventilation device on top of the building those people were living in. Very interesting matter.

anyway, any music listened too loud for a long period of time will cause vertigo, nausea and an overall discomfort. depending on the quality of your headphones, the frequency response could be wider in the low frequencies than 20- 20000Hz, so that indeed the harmful ultra low frequency sounds will not be filtered!

Edited by greenback