Scale modulating sequencer

Plotted map

Modseq is a polyphonic MIDI step sequencer that can generate pleasant-sounding, evolving melodies.

It’s quick and easy to use, while still packing unique features and semi-advanced capabilities.

Modseq is built with Typescript, can run in a browser or as a standalone desktop app, and can use Web MIDI or built-in samples to generate its output.

Demo one
Demo two

Feature highlights

Clip-based patterns

Switching note patterns with clips is convenient, fast, and is a widely-understood metaphor in the electronic music world. Each clip is constrained to a musical scale — you can create nice-sounding melodies without any knowledge of music theory.

Polyrhythm support

In order to generate interesting rhythms Modseq has a feature of independent note track lengths. Just changing the lengths of two tracks to something like 7 and 13 will result in the rhythm repeating only every 91st time.

Scale modulation

Modulating from one musical scale to another is essential for melodically evolving patterns, but requires at least some degree of theory knowledge. Modseq is using a somewhat unusual system where each pair of scales and their transpositions is analyzed against each other, and the system hints to the user which keys are going to fit together. If that sounds daunting: just select the green-colored scale for each pattern and you are good to go.

Miscellaneous and planned

Multi-platform support — Modseq can run anywhere, where a browser can. Multiple styles and color theme support. On the road map: user-defined scales, arbitrary MIDI control messages per step, pattern-chaining with different modes, build for iOS devices, pattern regions editor and much more.

The process of designing and building the sequencer is described here.