i don't learn many songs, but the ones i do learn are usually quantum leaps in difficulty and often take a year to learn and work up to speed. my song for this year is "tango en skai" by roland dyens, after a few months of working on the tough bits, it's time to start stringing together the tough bits with the "easy" bits, which are still ridiculously tough for me. one of the things that has thrown me for a loop is 3 over 2 polyrhythms.

what is a polyrhythm?

if you've worked on the guitar fam fingerstyle course, you'll be familiar with syncopated rhythms, where the bass and the treble are not synchronized... such as in "deep river blues" and other songs. in a synchopated rhythm, the bass may keep a constant beat (say half notes) while the melody does it's own thing (say quarter and eighth notes). the melody and bass plucks often don't line up, and are thus syncopated.

a polyrhythm is where the bass and melody are not only syncopated, but also follow different rhythms. for the tango, the polyrhythm is 3/2, which means the melody is triplets while the base is eighth notes. here is an example:

counting time for polyrhythms is quite difficult, even for the basic 3/2. generally you count a 3/2 as "one trip-and-let". i can manage that on it's own, but jumping from eighths to 3/2 and back again takes some getting used to, and my timing ends up off a bit. most metronome apps do not have a dedicated polyrhythm setting.

here's how to make most metronome apps count out any polyrhythm...

start by multiplying the two rhythms (3x2=6 for 3/2) and creating a time signature x*y/4 (in my case, 6/4). then figure out which beats the melody needs. for triplets, this would be every other beat, thus beats 1, 3, and 5. then figure out which beats the bass needs. for the standard eighth notes, it would be beats 1 and 4 (the halfway point). set one sound for the initial beat, one sound for the remaining melody beats (3 and 5 for me), and one sound for the remaining bass beats (just 4 for me). all other beats should be set to silent (2 and 6 in my case). multiply your overall tempo by x*y (in my case, 30 bpm practice x 3 x 2 = 180 bpm).

here's a screenshot of my 3/2 polyrhythm setting for 30 bpm in soundbrenner:

both the melody and the bass are played on click 1, nothing on click 2, the melody on click 3, the bass on click 4, the melody on click 5, and nothing on click 6.

this setting is also very handy if you have a song that jumps from triplets to eighths and back. with this setting i can work on stringing together the bits with eighths, triplets, 3/2, and even the sextuplets and hemidemisemiquavers. i will likely have this beat playing for the next month while i sleep to ensure it gets fully engrained in my memory 😁.

what does it sound like? well, it goes a little something like this...

thus ends today's metronome hack. happy plucking!