The best solution for mastering is to use couple of different pairs of monitors
and different rooms, one room accoustically threated and the other one
completely naked. Near-field monitors, mid-field monitors and stay-away-field
monitors (pa speakers). Btw, Sony studios have a special room with a real
car inside, that equipped with a decent car stereo system - that's some
original and very good idea for mastering purposes.
Ofcourse most important is always to keep a pair of good and fresh ears.
