We make two different sizes of drivers: 5 and 9 inch.  As can be expected, the 9 inch has a larger sound, the 5 inch has a slightly greater finesse in the high frequencies.  Please choose according to your room size, though we should note that the "smaller" 9 inch drivers, I.E. the Naturflux units, can also work well in small/medium sized rooms.  Also, the "larger" 5 inch units I.E. the Type II and III really shine when given a large room in which to breathe.  In the end, it is all according to your taste in music reproduction.  All of our full range driver units are the best at what they do.  For advice regarding driver choice, please do not hesitate to ask us directly.