No drummer has labored to redefine the drum set as vigorously as Terry Bozzio has. When he began to explore the harmonic and melodic possibilities of his kit in the '90s, Bozzio single-handedly created a new category of drum clinician who uses the platform to perform drum set compositions rather than demonstrate the latest hot lick. We can't imagine a better person to ask how music theory applies to the drum set.
Some heavier bands like Mudvayne and Korn and Tool do very intricate odd times in their arrangements, and younger kids want to be able to play that stuff, so it's definitely important to have an understanding of that. All time signatures are broken down into twos and threes. By mixing up twos and threes using some simple addition you can pretty much count anything that's out there. By starting with something as simple as right-left for two, and right-left-left for three, you can make elevens, sevens, thirteens, fifteens, and whatever else you want. I make a little chart that deals with the permutations of twos and threes in basic odd time signatures. For five it's easy – just a two and a three or a three and a two. And then for seven you've got two-two-three, or three-two-two, or two-three-two. And with nine you have three twos and a three, and then you take the three and you move it, so you then have three-two-two-two, and then two-three-two-two, and then two-two-three-two, and back to two-two-two-three. And then there's also three-three-three. The Louie Bellson Odd Timebook is a great place to start if somebody reads and wants to take the book route.
Note value and duration is an overlooked area in drumming because our drums and cymbals have indefinite duration, which is why we tend to think only of the attack. You can write anything out as sixteenth-notes and sixteenth rests and play it on a drum set, and it would probably sound exactly the same as if you wrote it out in longer duration note values, like eighth-notes and quarter-notes, dotted eighths, half-notes, what have you. When drummers become a little more advanced they begin to realize that everybody else in the band is playing note values and durations, so if they want to play with them, they need to understand that. And where that comes into play for drummers is using the roll, which is the drummer's long tone. Rudimental five-, seven-, nine-, eleven-, and thirteen-stroke rolls all have to do with rolling for a certain duration of time.
The drummer who plays loud and fast all night gets boring, because you've heard it, and after one song it's just the same thing all night. It doesn't get any louder. It doesn't get any faster. And on the other hand, the drummer who plays laid back all night long is boring, as well. But the guy who can mix it up and can play loud and soft and fast and slow adds contrast and engages the listener by doing something unexpected. A lot of adjectives can be applied toward the use of dynamics that span lots of different emotions. Something louder seems more aggressive; something softer seems more warm and intimate. Something louder seems closer; something softer seems farther away. So you get this spatial element. Something louder seems brighter; something softer seems darker, so you have gradation of light. All these things can be applied toward the kind of feel you want to get for your music to add contrast.