I wanted to share a video for feedback that my wife made comparing two vacuum record cleaning systems - the Okki Nokki One vs the Squeaky Clean Mk3.
I think it's great to see someone talking about record cleaning and showing some actual evidence using the microscope. There seems to be a lot of advice around on what contaminants effect vinyl records (e.g. "oils", "debris", "particles", etc), as well as the best cleaning methods and cleaning agents. However, I've not seen a lot of objective evidence supporting this.
I just grabbed an old school lab microscope to take a look a few of my records and it was quite interesting.
In a small sample of new records, the predominant contaminant seemed to be metal flakes (nickel? Also visible in the OP's video) I presume is from the stamper? Difficuilt to say whether these are audible. The vast majority can't be, as there are thousands across the records surface and a new record might only have a handful of crackles:
Some are larger like this one and possibly audible:
On older records suffering from pops and crackles (even after ultrasonic cleaning) I could see particles stuck within the groove. This lump of unidentified 'rock' almost certainly is audible:
I also looked at a new UHQR record from Acoustic Sounds. These are supposed to be amongst the best of the best. Uncleaned, straight from the sleeve, it looked fairly 'dusty' but didn't seem to have the metallic contaminants of regular records:
After ultrasonic cleaning of the UHQR record, the surface looked free of contaminants. Subjectively, this UHQR record sounds great, so it's good to see it's nice and clean:
Finally, looking at the record's grooves makes me doubt whether "oils" left over from the stamping process could be a major issue. Firstly, I didn't see evidence of oil within the grooves of uncleaned records. Secondly, the undulation and contours of the groove are quite defined at a microscopic level, so it feels difficult to believe that a coating of oil could change the contour to such a degree as to be audible. Obviously, an oily surface is more likely to hold contaminants, but on a clean record it seems unlikely that residue oil alone could significantly impact sound quality?