Many smaller propellers can replace a few bigger ones. They'll make noise but not nearly as much as huge twin props. Another thing is that electrical propellers only make noise when you need them to produce thrust. Most traditional props produce noise just sitting on the ramp waiting for their oil temperatures to rise or while slowly taxiing to the runway. Another difference is that the high pitched whine of an electrical engine is very different from rumbling of a jet or piston engine. As I'm writing this, I hear a jet plane taking off from an airport 6 miles away from my house. I doubt I'd be able to hear an electrical plane from that distance.