I too have a fluid trainer (Cyclops Fluid2), and I'd hardly call it 'silent'. I think a lot of it depends on what kind of surface you're riding on... if you're in a typical older Toronto house I can nearly guarantee they'll be able to hear it below you. My old neighbors could as I asked them about it after I got mine. Since I was doing most of my riding early in the morning I just moved it out into the front of the apartment since their bedrooms were at the back of the house. I never got any complaints.. *Shrug* I've wondered about those mats as well as I think most of the noise is just from the thing vibrating on the floor. That might be why yours seems quiet, iherald, if you have it on a concrete basement floor. It also depends on how fast you're going though. If I'm just warming up/cooling down or going for a small ring spin, it's not too loud. But doing intervals can get pretty loud spinning at 90+ rpm in say 52x18.

As a side note, my cats are pretty scared of my trainer, but you can't count on kittens to exhibit 'normal' behavior.