I have not found a linear piston air pump that is quiet enough that I'll use it in my bedroom. If you plug one in and run it dry (no load), it's pretty loud. But once you add the load to it, it's actually pretty quiet -- just not so quiet I'd run it in my bed room.
I have this one
(cheaper if you spend 2 more minutes searching, I'm just using it to show the model). I use it to run 7 double sponge filters, 8 air stones, and I can still squeeze out more air to use. This one is only 18w, there are more powerful model. Coralife has a similar one too.
The key though, is to lay out the air tube properly so none is too long, and choose good quality gang valves. You can test the gang valve by submerge it in water while connected, you shouldn't see bubbles. I have tried all the plastic ones I can find, none passed... so I got the metal ones (very hard to find) and they are much better. Some of the metal ones leak too but not as bad, plus I think they last longer.
I have four tanks in my bedroom too... I use 2 x Fluval Q2, each one for two tanks, each tank get a sponge filter and an air stone, and I can probably add one more to each but no more than that. Q2 is really quiet, the bubble noise is louder than the pump.