Progressive Drumming Essentials
Part 10: Implied Metric Modulation Madness
by Aaron Edgar
People commonly hear music with a bass drum on beat 1 and backbeat on beats 2 and 4. Using different subdivisions, we can spread out the backbeat spacing to imply that time has slowed down or compress it to suggest a faster tempo. In these first examples, we’re going to slow down an 8th-note rock groove by trading our 8th notes for dotted 8th notes, which are equivalent to three 16th notes.
If you have trouble making Exercise 2 feel solid, try counting 16th notes out loud (“1e&a 2e&a 3e&a”), and start with the ride cymbal only. When you feel comfortable with that pattern, slowly add the bass drum and snare.
You may have noticed that your ride cymbal in Exercise 2 creates a four-over-three polyrhythm. Metric modulation is a great tool for exploring polyrhythms, and we’ll examine this application more at the end of this lesson.
Once you get the hang of it, try playing Exercises 1 and 2 back to back for eight bars each. If you play quarter notes with your hi-hat foot, it will reinforce the original pulse and can be beneficial if you’re playing these ideas with other musicians. When I’m learning new modulations, anchoring time with my left foot helps me internalize the rhythms.
It gets interesting when we embellish this type of modulation. We can create the same effect of slowing down when modulating a 16th-note triplet groove into 16th notes.
Now that we’ve experimented with a modulation that sounds like it’s slowing down, we’ll speed up an 8th-note- triplet-based shuffle groove into 16th notes.
Next, try a less ordinary pattern. Exercise 7 is a funky, syncopated groove with an irregular ride pattern. Applying this phrase within 16th-note triplets yields a hypnotic two-bar phrase in 4/4.
This modulated pattern could sound like its own triplet groove. It’s a perfect example of how we can use modulation as a writing tool, and we might not have come up with this using any other concept.
The Polyrhythmic Connection
I mentioned earlier that you can use implied metric modulation to create grooves based on polyrhythms. In Exercises 9–11, we’ll go through the process of writing an implied metric modulation groove starting with a polyrhythm.
For Exercise 9, we’re going to use a four-over-five polyrhythm. We’ll space four notes evenly across a bar of 5/4 time by playing every fifth 16th note. Playing quarter notes with your hi-hat foot will accentuate the polyrhythm.
The next step is to fill in the spaces with the bass drum and ghost notes. I’ve phrased our ride cymbal to sound like a drunken shuffle by playing the first and fourth note in each of the five 16th-note groups.
Finally, we’ll modulate this groove into 4/4 using quintuplets. This gives us a backbeat on beats 2 and 4 again. Both rhythmic variations of this beat create interesting shuffle-style grooves.
Make sure you try modulating a handful of your own grooves. Take a groove you play all the time, or transcribe a beat from one of your favorite bands and modulate it into something new. I often find that there’s something inspiring hidden within a new subdivision.
Don’t forget that you can also apply other rhythmic tools. Think about displacing the modulations, cutting pieces out, reversing sections, and reordering parts. You are limited only by your imagination.
Aaron Edgar plays with the Canadian prog-metal band Third Ion and is a session drummer, clinician, and author. You can find his book, Boom!!, as well as information on how to sign up for weekly live lessons, at aaronedgardrum.com.