The band was about to play their final number and the leader was introducing the band members one last time. It was a bit redundant because the line-up was a who's who of Canadian jazz players. Finally the MC announced the drummer, adding that he was the glue that held it all together, and all the band members nodded in agreement.
That struck me as a bit odd. These were simply the ‘best of the best’, so why would any glue be required? These musicians could do anything. Still, the consensus seemed to be that the drummer was the one who kept things on track.
It's both a flattering and an intimidating assessment. It's nice to have someone say you're such an important part of the ensemble, but its also a lot of responsibility.
In a way, the drummer is the ‘floor manager’ of the music. While the leader may pick the tunes, set the tempos and kick things off, successful completion of a tune requires someone to take care of how it all develops. And the drummer is the ideal choice. A good drummer, one with the right skill set, helps to illustrate the time, solidifies the rhythmic structure, marks the different points in the tune, and manages the energy level during solos and different sections of the tune.
A drummer has quite a bit of power. Even in a high-volume situation, the drummer can usually compete, and our drive (or lack of) can have a big effect on the music. We're like the tiller of a ship. We can determine the direction with a simple adjustment. We can also make things a bit scary if we're too heavy-handed on the tiller.
A drummer is a go-between. We communicate the time and energy to the other band members. For example, in a jazz band, the bass player's job is to lay down a steady bass line. The drummer can then help communicate the time to the other players. This will also give the bass player more freedom and lighten his/her load.
And we’re arbiters. If you have two musicians pulling in opposite directions -- guitar player plays on top, bass player plays behind, for example -- the drummer can find a spot in the middle and help these two work together.
Sure it's a big job, but somebody's got to do it.