My wife and I share a plugin hybrid and an EV. You'd think the EV is as loud, because you notice the air and tire noises in the absence of the engine noise.

But in the plugin hybrid, the change in noise is very noticeable when the car goes from pure EV into hybrid and the engine kicks in. It's specially loud when the engine revs up as you're accelerating, but even when the car is cruising, I can still hear the engine noise.