Higher efficiency speakers often do sound better than low efficiency, and can do so by a wide margin. But, some lower efficiency speakers do sound pretty darn good at low volumes.
I agree that loudness controls are a huge help--yet, as stated above--they are nearly extinct. I have a preamp with tone controls. I use them about once or twice per month--typically when I want to work while listening or read. At low volumes they do not impart distortion that I can hear or that bothers me. As I tick the dial up, I don't like them or use them as much. It's nice to have a tone defeat.
I agree that loudness controls are a huge help--yet, as stated above--they are nearly extinct. I have a preamp with tone controls. I use them about once or twice per month--typically when I want to work while listening or read. At low volumes they do not impart distortion that I can hear or that bothers me. As I tick the dial up, I don't like them or use them as much. It's nice to have a tone defeat.