JBL makes a number of powered studio monitors which would probably be a good idea. They work great in far-field situations like restaurants.
The one issue is the size of the room. The difference in volume between the front and the rear will be unusually large, not sure if you wouldn't be happier with 2 monitors per side. This lets you keep the volume low, but equal.
The one issue is the size of the room. The difference in volume between the front and the rear will be unusually large, not sure if you wouldn't be happier with 2 monitors per side. This lets you keep the volume low, but equal.