I've danced to bands with three musicians and to bands with twenty, as long as the rhythm and phrasing are clear, it isn't any louder than it needs to be, and the music sounds good, then it will be a good evening. The possible risk with a bigger, informal band is a "muddy" sound with people doing their own thing.

I know of one band who predominantly play Irish ("Celtic rock") and have found them very hard to dance to when they do a barn dance, because the rhythm wasn't clear for stepping. Too much emphasis on being fast and clever.

A good punchy rhythm will not only keep the dancers "in step", it helps novices, gives a lift to tired legs and encourages people on to the floor.

The Watch (and more recent derivatives) can achieve this with three musicians and no percussion or bass; the larger bands I've danced to tend to be morris musicians, a lot of boxes and often again no percussion, but used to keeping feet moving.

Malcolm