Of the high-efficiency single-driver speakers I've heard, the Rethm is my favorite. It's also priced quite a bit lower than some of its competition. The thing that wins me over is it does't have the characteristic "Lowther shout" that most exhibit, due to an ingenious little paper shield-on-a-stick that goes between the main cone and the wizzer cone. Nope, I don't sell 'em... yet.