What is sonification?

The concept is simple: you turn data into sound. Obviously, you can play with frequency and volume, but there are more subtle sonic things you can play with to represent data. Let's imagine you had sales data for different countries and the data went up and down with time, you could assign a different instrument for each country (e.g. drum for the US, piano for Germany, violin for France), and different sales volumes could be represented as different notes. The hope is of course, that the notes get higher as sales increase.

If you have more musical experience, you could turn data sets into more interesting music, for example, mapping ups and downs in the data to shifts in tone and speed.

(Gemini)

Examples

Perhaps the simplest sonfication example is the one you've probably seen in movies: using a Geiger counter to measure radiation. The more it clicks, the more radiation there is. Because it's noise rather than a dial, the user can focus their eyes on where they point the detector and use their ears to detect radiation. It's so simple, even James Bond has used a Geiger counter. In a similar vein, metal detectors use sound to alert the user to the presence of metal.

Perhaps the best example I've heard of sonification is Brian Foo mapping income inequality along the New York Subway's 2 line. You can watch video and music here: https://vimeo.com/118358642?fl=pl&fe=sh. He's turned a set of data into a story and you can see how this could be taken further into a full-on multi-media presentation.

Sometimes, our ears can tell us things our eyes can't. Steve Mould's video on "The planets are weirdly in sync" has a great sonification example starting here: https://youtu.be/Qyn64b4LNJ0?t=1110, the sonficiation shows up data relationships that charts or animations can't. The whole video is also worth a watch too (https://www.youtube.com/watch?v=Qyn64b4LNJ0).

There are two other related examples of sonification I want to share.

In a nuclear facility, you sometimes hear a background white noise sound. That signifies that all is well. If the sound goes away, that signifies something very bad has happened and you need to get out fast. Why not sound an alarm if something bad happens? Because if something really bad happens, there might not be power for the alarm. Silence is a fail-safe.

In a similar vein, years ago I worked on an audio processing system. We needed to know the system was reliable, so we played a CD of music over and over through the system. If we ever heard a break or glitch in the music, we knew the audio system had failed and we needed to intervene to catch the bug. This was a kind of ongoing sonic quality assurance system.

What use is it?

Frankly, sonification isn't something I would see people use every day. It's a special purpose thing, but it's handy to know about. Here are two use cases.

The obvious one is presenting company data. This could be sales, or clicks, or conversion etc. With a bit of effort and musical ability, you could do the kind of thing that Brian Foo did. Imagine an investor presentation (or even an all-hands meeting) with a full-on multi-media presentation with charts, video, and sound.
The other use is safety and alerting. Imagine a company selling items on a website. It could pipe in music into common areas (e.g. restrooms and lunch areas). If sales are going well, it plays fast music, if they're slow, it plays slow music. If there are no sales at all, you get silence. This is a way of alerting everyone to the rhythm of sales and if something goes wrong. Obviously, this could go too far, but you get the idea.