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How to make the ball play a melody on every collision
Actualizado el 13 de septiembre de 2026
By default, every collision in Simbounce plays the next note of a musical scale. With an imported melody, every collision plays the next note **of the song**: the ball reveals the tune as it bounces. It is the most recognizable subgenre of the format, and the editor does it without any extra software.
Paso a paso
- 01
Get a MIDI file of the melody
The editor reads ordinary .mid files, with one or more tracks. Pick a melody with clean rights: your own composition or a public-domain work — the guide explains how to decide that below.
- 02
Open the Sound panel and import the melody
Click Import melody (MIDI) and choose the file. The panel shows how many notes were read. If the file is not a MIDI the editor understands, it says so instead of playing silence.
- 03
Listen in the preview
Turn on preview sound and watch. The melody replaces the scale: while it is active, the note of every collision comes from the song, in order, and wraps around when it ends. Instrument and volume still apply.
- 04
Fit the scene to the song's pace
A slow melody wants fewer collisions; a fast one, more. Move Balls, Gravity and Restitution until the number of collisions gets close to the number of notes you want to hear — the seed search shows the count for every candidate.
- 05
Export with audio
The export renders the track together with the video, synced to the collisions. If your browser cannot encode audio, the editor says so before starting; the server render always includes the track.
What happens to the scale
Without a melody, the sound panel picks notes from a scale (major, minor, pentatonic), a root note and a mapping — for example, impact speed to pitch. With a melody, the order of the notes is the song's and the mapping decides the rest: dynamics, length, timbre. Remove melody brings the scale back.
Scenes that follow the melody's grid
Some scenes read the melody differently: instead of playing one note per collision, they use the song's rhythm as the grid of the physics itself. In Fourier drawing the stroke advances on the melody's grid; in Numeric trajectory the grid comes from the sequence of the starting number. These are scenes where what you see and what you hear come from the same source.
Rights: what you can and cannot use
A MIDI file is sheet music, and sheet music of a protected song is still protected. Publishing a video with a current song, even as MIDI, can get removed or demonetized by the platform. Use your own composition, or public-domain works — most of the classical repertoire before the twentieth century, hymns and traditional songs. When in doubt about a specific arrangement, pick another one.
The advantage of writing your own melody is that it becomes a signature: the same theme across every video on the channel is what makes someone recognize the video without reading the name.