There comes a time in the life and playing experience of every bassist when someone in the band goes off piste and into a polyrhythmic or polymetric tangent as part of their solo or accompanyment, just to mix things up in the groove to keep it interesting for themselves (or as a bit of a joke to see who's paying attention).
Some acts have literally built their entire careers on this stuff (looking at you Tool...)
For beginners, when this happens, you have 2 choices: you can completely shit the bed or you can stay on target.
It can literally be terrifying when you suddenly realise that you're not technically locked in with anyone anymore and that the entire damn thing is hanging off you!
I want to try and help you understand what's going when this happens; it involves 3 core concepts that are all about manipulating the Time and Rhythm of a piece of music:
Learning about these will help because getting this right is a combination skill that requires bith listening intently AND completely ignoring a lot of what you can hear. It takes practice and knowing the mechanics of what's happening around you.
If you want to jump to the TL;DR, I've got you covered. Click here.
Otherwise, let's dive in...
Let's get the really math's heavy one out the way first. Any piece of music that has people playing
is Polymetric (Many Meters).
In the example below, the Drums are playing in 3/4 and the Bass is playing as single note on the 1 in 4/4. (limitations of the transcription software not allowing for different Time Signatures to appear on the same score...)
They sync back up again after:
This is a core concept to grasp to help you locate yourself in the music; if you're in 4 and the drummer goes to 3/4 the then every 3 bars you play in 4/4, you'll sync up with drums again.
It gets more complex and "mathy" when the Time Signatures that the drummer chooses are more "exotic" but they WILL re-sync in time and over a set, rememberable number of bars.
Here you can hear and see the contrasting patterns looping back around to the 1. In this instance, they arrive back at 1 after:
Let's look at something a bit spicier: 4/4 in the bass over 7/8 in the drums. (I know, the sheet music for this one looks a bit messy but stick with it!)
In this example the pattern loops back to the 1 after:
Note: in bar 5 there is a "false" 1 that you need to be aware of!
Below are 3 audio clips; one is the Bass and Drums with a click, one is Bass and Drums without a click (more difficult) and the last is just the Drums (sorry, you're going to hate me!).
Here's your exercise: play the notes in the green boxes.
Use the one with the click to learn the part and the feel of it, then play along to the one without the click to see if you've cemented the sense of the "true" 1 and can feel it in your body.
When you feel like it's something you can really feel, take the Drum Only track and practice it with that; maybe take the mp3 file and put it in a DAW and record yourself playing along to it to see if you really have nailed it?
The tendency, when there is no pulse at the Tempo and in the Time Signature you're playing, is to latch on to the most regular pulse you can hear. In the Drums only audio clip it's the Hi-Hats on the 8th Notes.
You need to be able to feel YOUR QUARTER NOTES under all of that busyness and keep it solid.
If, in the song, the whole band changes Tempo en-masse, the song has undergone Genuine Metric Modulation (this is a complex subject made even more complex by something called "Implied Metric Modulation" and you can read about it here in Part 1 of 2).
Metric Modulation has occurred if the song or piece has gone from say, 95bpm up to 190bpm (Double-Time) or down to 48bpm (Half-Time) or perhaps it's gone from a Quarter note 4/4 to a Dotted Quarter note 6/8; in these instances the entire thing has changed tempo and/or feel.
In the example below, the song has gone from a driving 4/4 at 115bpm Qaurter note tempo to a slower, more pendulum like, 6/8 at 52bpm with a Dotted Quarter note Tempo.
It has changed Time Signature, Tempo and Subdivision value so it has completely Metrically Modulated.
As I say, I go into much more detail about Metric Modulation here and it's a bit of a tricky one and I'm sure there will be plenty of opinions!
Polyrhythm is where the Rhythmic Subdivisons across instruments is different but they maintain the same Tempo.
For example you could have the Drums playing a straight 4/4, driving rock beat but the song is using a pattern of 2 Dotted Quarter Notes and a single Quarter Note over the top to create a lopsided, emphasised feel to it all.
Try this as an exercise: with one hand, tap a count of 3 mid tempo beats on your leg; on the other leg with your other hand, tap out 2 beats. If you managed it you've just played either 3:2 or 2:3 depending which hand you were leading with.
This pattern is called a Hemiola.
If you can tap 3 beats on one leg and 4 on the other you may be a Drummer!
Musically this may happen where someone starts playing in 3/4 while the rest of the band is in 4/4. If this is the drummer then it's all on you to keep it tight and make sure you know where the 1 is at all times.
In these instances it's a combination of all 3 of these concepts; an instrument is playing in 3/4 while everyone else is playin in 4/4 so that instrument has Metrically Modulated to a new Time an is now playing both Polyrhythmically and Polymertrically!
In any case, it's a fairly safe bet that any decent drummer that can do this stuff DOES know where the 1 is and will expect to meet you back there!
These are some quite complex ideas that take a little time to get your head around; just know that any or all of these may be happening when you're left hanging out there trying to keep it all together so it's a good idea to understand what they are and how they work.
I hope this has helped a little bit. Remember:
As mentioned earlier there's something called Implied Metric Modulation which you can read about here in part 1 of 2.
It's a bit of a tricky and some might say subjective but it's absolutely worth getting at least familair with as a concept.
