The Drone Is the Clock: Keeping Time Without a Metronome
Short answer: There is no fixed tempo. The long bars on screen are drones, and while one is sounding it gives a slow, soft pulse. Short sounds lean toward that pulse so they land together. When the area around the drone gets crowded, the pulse quickens a little. When no drone is sounding, nothing keeps time at all.
The problem
In this app sounds start when shapes touch, as described in Sound Only Happens When Things Touch. Contacts happen whenever they happen. Left alone, a burst of them comes out as clutter: several small sounds, each slightly off from the others, with no relation between them.
The usual fix is a metronome that everything snaps to. I didn't want one. A fixed tempo is a beat, and a beat is something to follow.
What I did instead
The bars are drones: long, low sounds. While a bar is overlapping another shape it sounds, and it gives a soft pulse every few seconds. That pulse becomes the clock. When a short sound is triggered, it waits a moment for the nearest fraction of the pulse and starts there, with a little looseness left in so it doesn't sound mechanical. It never waits long. If the wait would be noticeable, it plays straight away.
So the timing comes from something you can hear and see. Take the drone away and the clock goes with it.
It listens to the room
The pulse is not steady either. When the area around a drone is crowded with shapes, the pulse gets a little quicker and the drone a little fuller. When the shapes spread out, it slows down again. The busier the picture, the more the sound leans forward.
Three worlds, three kinds of pulse
- Ocean: a soft, low thump, like a slow heartbeat or a sonar ping.
- Forest: a quiet bowl strike in place of the thump. Nothing in that world has a hard attack.
- Space: no pulse at all. Short sounds play the moment shapes touch. It is the only world with nothing keeping time.
Ocean is free. Forest and Space open with a one-time payment.
What I'd tell someone building something similar
A clock doesn't have to be a separate thing. If one of your sounds already has a rhythm, let the others follow it.
Try it: in Ocean, watch the long bars. When one overlaps another shape you will hear the pulse begin. It is free and starts in one click.
Open Ocean, free