Unique Rooms and SPL in Large Areas:
Are there any special considerations for bathrooms?
Bathrooms are irregular rooms, rooms within a room, with high ambient background noise, often with noise masking type of ambient sound, highly reflective, and often fairly large. If you pause and think about that for a moment, these are some of the more challenging rooms.
Commercial noise masking systems rely on "white noise" which sounds remarkably like a bathroom exhaust fan and like the sound of water in a shower-- both of which are louder than the background noise level in the other parts of the house. So if the client wants to rock out in the bathroom, and particularly the shower, you need to have speakers very near to them. Modern day larger bathrooms need more than two speakers for these reasons.