Metric Modulation Simulator

The first is called metric modulation, which means that a note value from one pulse (original) equals another note value in the new pulse, thereby shifting the tempo. This allows you to listen to how these two grids interact in real-time.

It’s operated via your mouse; simply click on the controls or use keys on your computer keyboard if you’re navigating more quickely.

How to Use Metric Modulation

To get started, set your source tempo on the right side of interface. You can either enter a beats per minute value directly into input field or tap the tempo pad three to eight times to determine speed based off your own rhythm. For those who’d like to control it via their keyboard, tapping current tempo is as easy as pressing T key anytime.

In the large status readout at the top, the widget show both your source BPM and the resulting target BPM as well as mathematical ratio between them.

Select which rhythmic values you want to mesh next. For this, there are five possible values for the new pulse (the one on the right bank) and five possible ones for the old pulse (left bank). Options include sixteenths, triplet eighths, dotted quarters, eighth notes, and quarter notes. To select an option, simply click on it, or use the left/right arrow keys to move between choices when a button has focus. A brief sample of each option will play out as you hover or move around.

After selecting the old and new values, it’s time to make that connection. To do so, click on the tooth coupled button and they’ll be locked together. You can also turn coupling on and off using M key on keyboard. If on, the widget will display equation underneath in the bottom right corner where you see how the old beat relates to the new beat for your new tempo. The gears in middle visualization will also light up to show when something is being transmitted.

The transition from one tempo to the other can be set in two modes. Snap cut mode is a simple switch from one quarter note grid to another with no connection, it allows you to hear how the two grids match up. Bridge mode gives you a continuous stream of common note value pulse playing so you can hear the unchanging tick that connects the two grids. You switch between them using S key for snap cut and B key for bridge. Depending on your choice it will either sound like an immediate change over or something gradually overlaid.

Pressing the drive tempo pivot button will allow you to hear it shifting into place. If the controls are locked, you can press the G key to initiate playback. When playing back, this widget will cycle through the new grid, then it will play the transition. Finally, it will play the old grid. A series of lights show which phase is being heard. Lamps illuminate source, the mesh and target phases. Pressing the G key or brake button will halt the sequence at any point.

To save the currently active modulation into a drive train, just hit the commit button. This then lets you string several temp shifts together where each stage use the output from previous one as its input. Below the main control is the ‘chain’ panel, which shows history of added modulations. To go back and undo a stage, or restore to the start, hit relevant button. It’s great fun for experimenting with elaborate poly-rhythms in stages.

On the right is a slider that lets you adjust the master volume. A percentage shows up below to show your current volume level so you can adjust it to suit your comfortabely level.

If you prefer to have more room on your screen for timeline and other animations of gears, tap the fullscreen button in the top right corner of the widget to expand it all the way across your screen.

The following example begins simply, with a 2:3 ratio. A quarter note is coupled with a dotted quarter from the source. You can listen to how this new grid sounds slower or faster than before. Try changing the pulse values to see what effect dividing the beat has on perception of density.

Keyboard shortcuts allow you to alter settings on-the-fly while listening to the sound. All key- and mouse-based controls are available as a convenient reference in the help panel. If you’re not sure where a control is mapped, simply click how to play to expand the section. This section includes a reminder of the key mappings and details about the rhythmic value conventions in the simulator. You can keep the help panel toggled open or closed while working your way through the various exercises.

Play around with all the various options for pulse values and transition modes. They have added some visual feedback that supports what is happening mathematicaly and how it translates audibly.

After getting familiar with the interface, experiment with chaining a series of modulations to generate a progressive rhythmic movement. Go play and see what this world of metric modulation opens up for you in terms of rhythm and your perception of time.