I've got a hypermag and that is pretty noisy. Dread to think how noisy a fan is.
I've put it on a rug that is on 1" of foam, which has quietened it a bit, as a lot of the vibrations were going through the floorboards. It is on the highest resistance setting so that the rpm is lower.
You could try making an insulated box to go around the fan, but it might get a bit hot.
I've got a conti trainer tyre, which was no quieter than a slick, but doesn't fall apart with the heat generated.
Hopefully my neighbours think it's the washing machine. I don't use it after 9pm.