It may be that our understanding of cleaning vinyl via ultrasonics is in its infancy. That means there is probably a lot of misunderstanding about what combination of variables yield optimal efficiency. Vinyl "safety", if you will, is part of optimal efficiency. Over the years of various vinyl cleaning methods there has been some scare factor that is alway in play. For example we still have remnants of fear that alcohol will cause damage to "my precious."
What we haven't seen yet are studies of a) particle and groove size relative to frequency, and b) frequency and groove deformation and resilience. Of course there are other variables: time, temperature, chemistry and agitation. I suspect such studies specific to vinyl records are not going to burst forth given the economics. (Though you never know - there are enough quirky professors out there that some may be audiophiles and engineers and have grant money to burn.)
So ... in the meantime we need to pool information and experience based on our real world efforts. That does not exclude USC system manufacturers, but some caution is warranted wrt marketing claims.
In the case of frequency alone, the relation between it and particle size is pretty much common knowledge. (Fwiw, the chart often cited, and linked above, associates to cleaning perpendicular magnetic tape, not vinyl records, but it still makes the point.) What is less discussed is the relation between frequency, particle size and time.
From my experience multiple frequencies applied in sequence are more effective than a single frequency. (Industrial cleaning often involves up to 7 different cavitation frequencies.) Consider that dirt (for lack of a better term) can be layered in terms of particle size.
Duration is part of the equation.
The longer you beat on something as hard as you can the more likely damage can occur.
I've been cleaning at 37kHz for 10 minutes then 80kHz for 10 minutes. I'm now thinking of varying that to something like: low for 5, high for 5, low for 5 and high for 5. If I had a third higher frequency, I'd put that into the mix as well. Can this make a difference? I don't know, but its worth exploring. (FWIW I have zero evidence my current regimen causes any damage or downside - any change to it is out of curiousity, not concern.)
Experimentation continues. See more at
The Vinyl Press.
If you try something or discover something, document it and speak up.
tima