For the sake of convenience, no matter the manufacturer, small centre channels are always a compromise and because of the design there is the added issue of an unwanted boost in the 300-500HZ range which gives the human voice, depending on placement, an unnatural sound. The vertical designs like the M2, although small, are more even across the frequency range, hence, a more natural sound from the human voice. Like has been said many times before, although not often practical, the ideal set-up is the same identical speakers across the L/C/R.

The larger centres like the 180 and 160 with the bigger drivers and bigger boxes eliminate a lot of the problems that exist with their smaller cousins by adding considerably to the frequency range and as a result, generally don't require that extra volume boost either.