the part that literally DISAPPEARS is the low frequence rumble. It's a vibration of the whole head, I can literally feel my front teeth clattering when the rumble is there. It's REALLY weird. After a year, I notice that it starts in the evening. Before I go to sleep, I hop on my exercise bycycle and do intense exercise for 5 to 10 minutes. I started doing this to get tired and sleep easily. But since I started doing it, I wake up in the morning and there is NO rumble, whereas previously was there most of the day together with a hiss. Even the hiss has improved. Also, for the last couple of weeks I have had NO night spikes, whereas in the past about twice a week I would wake up with a spike, and had either to get up (and it would go away after about 20 minutes), or I would crank up the masking and roll over and sleep (I use masking 24/7). Coincidences? I still don't know. But the no rumble thing has been very consistent. It makes me think that it might really be a vascular problem. I don't know. The hyperacusis seems not to be affected by intense exercise. BUT, on some days it's much better, for apparently no reasons.