I’m the person in question and, yes, we have slate floor throughout our house. So, no argument that we don’t have the best acoustics for noise dampening, but it’s the same situation for all the appliances in the house. Even though we’ve now put on the sound dampening hood, it’s still about twice as loud as our 48" built-in fridge. (Real fridge, not wine fridge.) The wine cooling unit has a much louder fan sound, in addition to a running, cooling hum, and seems more high pitched to me. (The sound hood has done the most to dampen that high-pitched whine noise.)
As for decibel meter reading … I downloaded a free one for my iPhone, so take actual numbers with a HUGE grain of salt. I just wanted some sort of a measurement beyond the subjective, “it sounds loud to me.” It’s not loud enough to damage hearing, that’s for certain, but in an apples-to-apples comparison (meaning: using the same flawed meter) it was a good bit louder, numbers-wise, than the running fridge and a bit less than the running clothes dryer, if that gives anyone a better perspective.
Filling it did, also, lessen the noise a bit. My original post was when I was running the unit empty, just to make sure it worked.
EDIT: My completely subjective advice if you do go with Le Cache is to go through either a dealer totally local to you, as in you can walk into their showroom easily, or go through Le Cache directly. Le Cache has been responsive, which is in large part, I strongly suspect, due to Mr. LeVine’s posting here, which I only learned about today (thank you Eric!), but my dealer, Vintage Cellars, near San Diego, has not really. Prior to sale, I selected them because A) we had no authorized dealer in our home state and B) when I emailed them asking questions about the units, they responded extremely promptly, while emails to Le Cache through their website went completely unanswered. But, in the end, it was Le Cache direct who helped me, at least I believe, more than Vintage Cellars, despite the fact they were, at least prior to all the issues, extremely nice people to work with.