A lot of the sound generated depends upon the "fill". That is to say, the ratio of cases to media. I find on my CV-500 that the noisier it is, the more violent the vibration and therefore the cleaner the cases seem to get.
I cannot seem to come up with the correct "fill" to make my CV-2000 work satisfactorily. Maybe because I never have 2000 cases to clean at any time.