Hey that’s a good question, I never actually measured the spindle. But it’s quite different, it’s the sweet sweet sound of making chips, I crave that! 
Seriously though, it’s more the sum of semi-loud devices that gets on my nerves (that @$*&#! VFD fan, the muffled sound of the vacuum under the enclosure, the chiller, and optionally the washing machine and dryer nearby)
By the way, I had a wild shower thought (literally) the other day, I could extend the cooling circuit to go through the VFD sink. Water-cooled VFD !
Yeah I know how it sounds (dangerous), but I wonder if I could just use a PC water-cooling [part that goes on the CPU] and attach it to the back of the humongous VFD sink. It would be away from the power area, and in the unlikely event of a leak, gravity would do its job and not soak the inside of the VFD.