There have been several times where I have laid down to meditate and not only did I start hearing the high pitched ringing I tend to hear ever so often quite obnoxiously, but the actual frequencies seemed to be modulating. Like the pitch would literally go higher and higher and back down again! So for say 10 seconds I would hear a ringing lets say at a "C note" and then it would raise to a D note for another 10 seconds, then to an E note - on and on and finally to the highest pitch possible, then back down again. Other times its not so much consecutive, but rather a low pitch for example to high pitch to and in between, etc. After hearing that sort of ringing a few times, idk I just felt there was an intelligence behind it. On psychedelics the sounds get even crazier. They become almost tangible, a lot like OBEs with the humming and pops etc.