Online Polyrhythm Metronome
Two rings, one shared cycle. Hear 3 against 2 — and see exactly where the two lines interlock.
How to play
The outer ring carries X evenly spaced pips and the inner ring carries Y pips. Both rings finish one full turn in exactly the same time — that is what makes it a polyrhythm. Where a pip from each ring lands together you get a coincidence: both voices strike at once, the pips flash dark and a solid spoke joins them.
Mouse / touch
- Start / Stop begins and halts the loop. The very first press unlocks audio (browsers require a gesture).
- Ratio chips (3:2, 4:3, …) load a classic polyrhythm instantly.
- Outer ring / Inner ring number strips (2–9) set X and Y. Changing either restarts the loop from the downbeat.
- Tempo slider or the − / + buttons set the outer pulse in BPM. The inner pulse follows automatically at BPM × Y / X.
- Volume sliders per ring plus a master volume. Mute silences a ring; Solo silences everything else. A silenced ring still flashes, dimmed, so you can watch the part you are not hearing.
- Reset stops playback and restores every control to its default (3:2, 90 BPM, nothing muted).
Keyboard
- Click the widget once so it has focus, then: Space start / stop.
- ← → tempo −1 / +1 BPM (hold Shift for ±5).
- ↑ ↓ outer pips X. With Shift: inner pips Y.
- 1 mute outer, 2 mute inner, 3 solo outer, 4 solo inner.
- R reset, F fullscreen, H this panel.
- Tab moves between controls; Enter or Space activates the focused one. While a slider has focus the arrows adjust that slider only.
Conventions
- Warm amber = outer ring (the primary pulse, low woody click). Cool teal = inner ring (high tick). Dark = coincidence.
- The dashed needle at 12 o'clock is "now". The rings turn beneath it; a pip sounds the instant it passes the needle.
- The ruler underneath is one cycle laid flat on the least-common-multiple grid — the finest grid that contains both rings.
Tips
- Start at a slow tempo and solo the outer ring, tap along, then un-solo and let the inner ring appear against your tapping. That is how 3:2 stops sounding like a mistake.
- Read the counting line: for 3:2 the cycle splits into 6 steps, outer on every 2nd, inner on every 3rd. Count "1 2 3 4 5 6" out loud once and the pattern is solved.
Press Start, then Solo one ring and count along.
It’s a virtual instrument that enables you to see and hear what happens when two different rhythmic patterns interlock on the spot. It can be controlled using your computer keyboard (for quicker adjustment) or by moving your mouse or trackpad around. What it aims to do is get you thinking about how separate pulses may slot into a single repeating cycle.
There are two sets of concentric circles, the amber circle outside represent the main pulse, while the teal circle inside holds its accompanying beat. These two circle complete one full rotation in the exact same amount of time. When pips from both rings align at the top, they flash dark and strike together. A linear ruler under the dial plots this whole process on the same grid.
How to Use the Rhythm Tool
To start/stop the metronome simply click on the big green button located at the bottom of the widget. This button will also turn on the audio in your browser. Alternately, if you don’t want to use your mouse, click anywhere inside the widget to select it, then press the spacebar to start and stop.
The help panel can be opened with H, while pressing F enters fullscreen mode giving you a bigger view. There is a series of buttons with numerals such as 4:3 or 3:2. When clicked, these buttons changes the rhythmic ratio and immediately load a selection of familiar polyrhythms into the widget. If you prefer to create your own ratios then use the segmented buttons for both the inner and outer ring to select pips count from two to nine. The widget will calculate the inner pulse speed based off the outer tempo setting.
Outer pulse: Use the tempo slider to change its speed. It ranges from thirty up to two hundred and forty beats per minute. To make exact adjustments, use the plus and minus buttons on either side of the slider. When the widget is in focus, press the arrow keys to increase or decrease the tempo by a single step at a time. Press Shift and then an arrow key to jump in increments of five beats.
The sliders allow you to adjust relative volume of each of the two voices. There’s a master volume slider for the whole widget as well as individual volume control sliders for each ring. To hear only one pattern at a time, click the Solo button for the ring you want to listen to alone. The other voice will be muted but displayed on-screen. Alternately, you can also mute any single ring without it being soloed. Dimmed-out rings will still have their animation going so you can see where it is.
Adjustments can be made on-the-fly, via keyboard shortcuts rather than reaching for that mouse. The outer pip count adjusts using the up/down arrow keys, while holding Shift and pressing those arrow keys adjust the inner pips. Number keys 1 and 2 mute/solo the outer and inner rings, respectively. Keys 3 and 4 do likewise. Key R resets everything back to defaults.
Begin by counting out loud as you play the outer ring on its own; tap the pulse of that one so your brain distinguishes the pulses. Next, when you’re feeling confident, unsolo the inner ring and hear where it lands with respect to your pulse. You can count the steps in the cycle out loud. It’s very clear from the ruler.
The two lines appear to go in and out of time with each other, making it sound trickier than play in polyrhythms. Always be aware that they will re-set together at the end of their cycle. You can also see this structure in the widget which highlights where this happens. Let the coincidence flashes anchor you into staying on time.
Experiment by changing the ratio to notice how it alters the density of the rhythm. It’s also intended as visual reinforcement for what you’re hearing. The needle on top points to where you are in time. Below that the pips spin around and flash when they make a sound. A linear ruler matches up to the dial ticks. It lets you see exactly how far through each pulse you’ve got. Mute one and observe the other and you’ll get an idea of how far apart each one is from the rest.
Try various extremes in speed. When you play slowly, it will allow you time to hear and feel the subdivision, while a faster tempo tests the limits of your hand/limb coordination to keep them independent. Whatever change you make, the widget reacts immediately, allowing for rapid iteration. See which one allows you to master the pattern best.
There’s no need for any previous experience with music theory to enjoy using this tool. The interface handles the math in the background. Simply select the number of beats per cycle on either side and away we go. A nice visual and audio representation of the relationship is then shown.
Experiment with complex rhythmic structures, practice your coordination, or use it as a warm-up exercise. Hit play and start exploring what interests you.