There Are No Audio Files: What It Means to Synthesise Sound Live
Short answer: Ambient Sound Online contains no recordings. Every tone, texture and echo is calculated in your browser at the moment you hear it, using the Web Audio API that every modern browser has built in. The whole app is about the size of a small photo, and it uses the same amount of data whether you listen for a minute or all day.
How to check
Start Ocean, then switch your phone to flight mode, or turn the Wi-Fi off on your computer. The sound carries on. There is nothing left for it to download, because there are no sound files.
I didn't know this was possible when I started. I'm a designer, and I assumed a sound app meant a folder of sound files.
A cook, not a vending machine
Most ambient apps work like a vending machine. Someone recorded a track once, and every press of play hands you the same one.
This works more like a cook with a recipe. The browser has a few basic ingredients. An oscillator hums a single plain note. A filter makes a sound brighter or duller. A gain control fades it in and out. Wire a handful of these together and the browser makes the sound fresh while you listen. Nothing is stored. The sound exists for as long as it takes to reach your speakers.
Even the room is calculated
The sense of a sound happening in a space is reverb. Normally you get it by recording a clap in a real hall and using that recording as a stamp. I have no hall. The app builds a short burst of noise that fades away the way an echo would, and uses that as the stamp. Each world gets a different one, which is why Ocean sounds submerged and Forest sounds like a temple. More in Reverb Without a Recording.
What you get from doing it this way
It never repeats. A recording is a fixed stretch of sound, so sooner or later it comes round again. Here the sound depends on where the shapes happen to be, and the whole tuning slowly slides up and down over a few minutes, so there is no stretch to come back to.
It costs almost no data. After the page loads there is nothing more to download. That matters on a phone plan. The cost moves to your device's processor, which I looked at in CPU, Battery, and Data.
It keeps playing if the connection drops. As long as the tab stays open, the sound doesn't need the network.
What it doesn't mean
It doesn't mean nothing leaves your device. The site counts visits and how long people listen, anonymously, like most sites. No sound is recorded and none is sent.
Sources
- Web Audio API, MDN: the browser feature all of this is built on
Try it: open Ocean and press play. It is free and starts in one click, with no account. Everything you hear is being made while you listen.
Open Ocean, free