And then, of course, there is the Fletcher-Munson curve to consider, if Mike is going to play music at low volumes. Given that, a small, high-quality monitor with a sub (or subs) might be a good choice. I suppose he could get an integrated amp with tone controls instead, but that wouldn't be my first choice.
Mikefi: what does "rather low volume" mean?
Mikefi: what does "rather low volume" mean?