Frequency of the ultrasonic is not the only consideration when trying to not only surface clean, but restore a record by removing its release agent. Simply putting a record in a machine that uses sonic technology of any frequency and spin a record for a fixed period of time may perform a light surface clean, shine up the look of the record, but that is all. In selecting a frequency and a sonic, one needs to study the item being cleaned, in this case a soft item, a record, commonly contaminated with dirt, fungus, oily fingerprints, McDonald's french fries oil, and dust, but not of any concern, bacteria (microbes), which has nothing to do with sound reproduction and the needle action with the grooves. 1) Ultrasonic microbial removal benefits from a higher frequency. (sub micron particles). This for hospital tools, colonoscopic cameras, silicon chip substrates and the like. 2) In the case of records, particles of dust and dirt, fungus caught in the release agent of the record are only three to four microns in diameter. Not sub-microbial, not bacteria. Any ultrasonic manufacturer whether medical or otherwise will agree where one will require a lower frequency such as 35KHz to dislodge and remove the targeted 3 to 4 micron sized particles from a "sticky", "soft" surface. (In our case we also add a resonance of 70KHz. 3) Ultrasonics 101: Irrespective of the frequency and sonic model selected: to actually benefit from the effect of cavitation one needs to also change the charge of the record to be opposite to that of water to fully attract the wave created by the implosion/explosion of the microbubbles created by sonic cavitation. Both the record and water in the sonic's tank, with or without a cleaning agent added in the tank of distilled water, have the same charge. NOT GOOD! Like charges repel. To change this reality, in our case (Kirmuss), we apply a bipolar ionizing surfactant spray to the record. With the record now having a charge opposite to that of water, in the first cycle in the sonic we start the "surface cleaning" process removing fungus, surface dust and dirt from the record. As the record spins, we lose the charge after 3 minutes or so, ... that is why we need another cycle with ionizing agent re-applied to the record. One cycle alone of 2 or 5 minutes is not complete. With the record charged again a second time, we now see cleaning action start deep within the record, first now removing the microwelded dust that lodged itself at the factory into the newly pressed and "hot" record that just came out of the press. (Heard as pops when a new record is played for the first time). As once more the charge of the record reverts to that of water, yet another cycle is needed using the ionizing spray, (moving forward in time), is now required to remove microwelded dust that we have ourselves welded into the release agent via the heat generated by the dyne of the needle by playing the record and our heating up the release agent seeing dust around the turntable lodge itself in the grooves. Then, in another cycle, finally removing the release agent itself. End result: With the release agent removed, one will never create another pop into the record while playing it. (manual needle drops excluded, of course). 4) Validation: The above said, one can compare the results at a an audio dealer processing the same record with machine brand A, (high frequency), and then processing the same record using brand B, (lower35 KHz frequency) and using an ionizing agent on the record. Following manufacturer's instructions and completing the process, one can hear the differences as well as see the increase in signal gain by a VU meter on an amp, preamp, or tape deck, or see where one has to "reduce volume" between processes. Of course one can review materials readily available on the web (or contact me) that show before and after 3D images with measurements of dust and dirt removed, as well as the microscopic imagery of the removed "release agent coating" as measured from the same record as a "before and after" image. About 9 microns average is the thickness of the release agent. If someone is familiar with our process, the safe and small proportion of 70% IPA in 1.78 gallons of water is used to kill dormant and live fungus from records so as to not affect one's health, rather that being part of the cleaning process. WORD OF CAUTION: Never use the Kirmuss ionizing agent on any record unless used in a Kirmuss product. Higher frequency sonics with an ionizing agent applied to a record may see damage to the record occur. I rarely follow posts and the like but in this case wanted to bring some technical reviews of records and sonic technology.
