OK, so I attempted to tune into the hum this morning and it was kind of successful. I woke up feeling distinctly suboptimal and decided to apply some of the principles I've been reading on the Nexus lately in order to get a better start to the day. I started off with some Wim Hof-ish breathing exercises, 3 cycles of about 20 breaths hyperventilating followed each time by holding my breath for 1 minute. That helped to reduce the physical pain I was feeling and it was energising as well as seeming to reduce inflammation to some extent.

I then tuned through my normal tinnitus into my inner silence while staying alert for whatever might be there. I then heard a rushing noise building up, like the sound of a wave breaking on the beach except that it started quietly and besides the white noise there was kind of a ringing resonance to it, perhaps like the faint addition of a singing bowl to the mix. This was accompanied by a sense of a white light illuminating from within and a divine spark of transcendent euphoria was kindled. Consequently I'm feeling significantly more functional than I have done for the past 12 days.

This is promising and intriguing - where does one find more literature and resources regarding this technique?

I might add, I did have 50mg of freebase harmine sublingually last night (3 a.m.) and this meditation was 6½ hours later. Prior to that, at around 11 a.m. the preceding day I'd had syrian rue tea made using 3 g of seeds.