Ultrasonic cleaning with kirmuss and loss of high frequency details.

Terry, "105db" at what frequencies?  This issue of hearing damage from US RCMs makes me realize that I am not sure what part of the physiologic chain that results in "hearing" is damaged by prolonged exposure to high SPL in the audible range.  Could be at the tympanic membrane or at the hair cells.  Do you mean to say that your machine makes a lot of noise in the audible range while generating UHF (which you cannot hear) that actually does the cleaning?  I could imagine that is possible.  The 2 or 3 different US machines that I have been around were not dead silent but they didn't seem to be dangerous with no ear protection.

I just Googled.  There is a whole Wiki article on this subject.  Seems the damage is manifested at the hair cells in otherwise young healthy persons.

I use Bose noise cancelling headphones when I do cleaning. The vac machine and the US machine are both very irritating and noisy

Bose, the enemy of SQ and truth in advertising.

@lewm 

105 dB at US frequencies. It's only a bit noisy at the 80 KHz setting, while irritating at 37. Still, nowhere near 105.