Ultrasonic cleaning with kirmuss and loss of high frequency details.

Like I said here last week, the question of whether US cleaning harms LPs can be asked in a fairly scientific manner using test LPs that encode pure tones at known frequencies. There is no real need to guess or go on subjective impressions.  Someone like HW is surely in a position to do the simple experiments.

One given principle is that excessive exposure to US, at the wrong frequency or for too long a time or at the wrong temperature or some combination of the three, has the potential to do harm. The question is where does that boundary between harmless and harmful lie, and how close does any good commercial US cleaner come to it.

Yes, wondered about his using that same brush multiple times in succession and then being surprised that he kept revealing that whitish deposit, which might well have come from the brush that was dirty from previous use.  But I gave him the benefit of the doubt in that I assumed he cleaned the brush between uses without mentioning it.  At least I hope so. 

What I do with my VPI HW17 is to clean (using the built-in brush) in both directions with a mixture of distilled, deionized water + 10% propanol + a drop of Triton X100.  Then dry with vacuum.  Then squirt some pure distilled deionized water on the surface of the LP and use the HW17 brush and vacuum to get rid of the excess cleaning fluid that may have lodged in grooves.  That last bit with unadulterated deionized water makes a difference. Takes me 2-3 minutes to do both sides of one LP.  I compared my method to one particular US machine, cleaned by the owner of the company, at the Capitol Audio Fest.  I chose one LP that had really good sonics but was stubbornly still a bit noisy after VPI cleaning.  All I could say was that the US cleaning made no significant improvement, and I could guess (not prove) that the noise on this particular LP was due to previous groove damage with a bad stylus, not to "dirt".  We sometimes forget that some LPs are not salvageable by any cleaning method.  By no means, however, do I claim that my little experiment proves anything about what is the "best" way to clean.  It only made me feel that I have little to gain by adopting the US method, which would add some aggravation that I don't need (until I am able to hire that butler).

I watched the video on the Kirmuss machine done during the 2018 RMAF.  I have no issues with any of the claims made, but I would never ever be bothered to go through that ritual with every single new LP I buy.  I already find that I waste a lot of time on "maintenance" (changing light bulbs, buying stuff for our house, fixing minor plumbing problems, etc.)  These constant intrusions have made me understand why some want to be very rich, which for me would mostly mean that I could pay someone else to perform those onerous tasks, which would include cleaning LPs with a Kirmuss or any of several other US machines or even my trusty VPI HW17, which is also a pain in the arse to use.  So, I need a butler, not a Kirmuss.

 I just noticed something funny, which maybe others have already noticed, and almost certainly the OP has noticed. When this thread was initiated it was about loss of high frequencies on the LP, in other words damage to the LP from ultrasonic cleaning. And then the topic suddenly changed to damage to one’s hearing from being near to an ultrasonic machine. Those are obviously two entirely different things. Maybe the OP can put us back on track.

Bose, the enemy of SQ and truth in advertising.

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.

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.

It might be subtly irritating to be around the US machine when it is in operation (via bone conduction and other ways we sense ultra high frequencies), but can your hearing be damaged by frequencies that are so far above the range of audibility?  The frequencies are an octave or more above 20kHz, are they not? It's an interesting question.

What I was trying to say to the issue of damaging LPs is that there are dozens of machines on the market.  They vary quite a bit as to the frequency at which they operate and to the energy imparted into the bath.  No manufacturer wants to be associated with a product that does damage, but human error can be a b**ch, so caution is merited, IMO.  A third factor that theoretically could contribute to a damaging effect and which is not under the control of the manufacturer is length of time in the bath.

There is a sort of "scientific" way to ask this question, if you have an oscilloscope or a very high quality AC voltmeter and the requisite test LP.  Play some of the pure tone high frequency bands on the test LP, record the amplitude of the AC voltages thus generated, which is easiest to do with a 'scope, and then wash the test LP one or more times in your machine.  Then re-test at the same frequencies.  It would be helpful also to have a second duplicate test LP that serves as a negative control, i.e., don't wash it in between the test procedures.  But since this is pseudo-science, I guess the negative control LP is not mandatory.

I too have read the warnings about loss of hf with US cleaning.  Seems to me it would depend upon the operating frequency and intensity of the US generator.  In other words, I feel very confident that if the US generator were powerful enough and if it operated at "the wrong" frequency (whatever that is), then an LP could be damaged.  Most manufacturers assure us that their particular machine is completely safe.