Has anyone else tried dampening driver whine with some soft material? I just tried it on a light that had it particularly bad and it seems to have worked pretty well, although not perfect. I just used some thermal putty (duct seal mixed with silicon carbide grit of a few sizes) around the springs. My guess was the springs are vibrating from the current (due to PWM) and they are the most unconstrained part of the circuit. Jumping the springs would probably reduce this but on this light only the rear is jumpered because the front is one of those short Nanjg springs and it’s a pretty mild build. Such a high frequency sound is very directional so if I hold it just so I can still hear it a little but it’s mostly gone.
I potted a very noisy FET driver with thermal adhesive and it did reduce the whine, but it was still audible and annoying when holding up close to the head. I also had another driver to make “shutter” noises when in strobe mode, it was driving triple XP-L close to 10A.