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How the reactable Works


Reactable Objects
The position of each object on the reactable's tabletop surface affects the outcome of the music, giving players a seemingly endless amount of choices.
The position of each object on the reactable's tabletop surface affects the outcome of the music, giving players a seemingly endless amount of choices.
Music Technology Group/Pompeu Fabra University

When you place one side of an object onto the reactable's surface, it's like pressing a button on a synthesizer and letting a noise or a beat loop over and over again. But just putting down one block would miss the point of the reactable -- there are several types of blocks, with different shapes and sides, and where you place one in relation to another affects the outcome of the music.

­There are six different blocks, each with a unique shape and function. Square objects are sound generators -- rotating a generator changes the frequency, and dragging your finger around an animated circle can increase or decrease its amplitude (how loud or soft the sound is), much like controlling the volume on an old television set. A sound can also be cut by making a "cutting" gesture to the line that connects the object with the center of the table, and you can turn it back on by touching the animated circle again.

Squares with rounded edges are sound filters, which process sounds by adding different effects. They perform the same thing a ­guitar pedal might, adding flange, fuzz or feedback-like resonance to the sounds the instrument would normally produce. If you had a sound generator giving off a steady, even tone, adding a sound filter next to it would distort the sound to make it more interesting.

Circular objects are controllers, sending control data to the objects closest to it. This will change the frequency of the sound wave -- for instance, you could either have a steady, flowing sound that goes on cleanly and uninterrupted, or you could vary the frequency and give it more of a wah-wah shape.

Control filters (octagonal, or eight-sided) and audio mixers (pentagonal, or five-sided) are more geometrically complex, and their jobs are in fact a bit more complex. The two types act as samplers and mixers, allowing musicians to create intricate melody loops and lines that harmonize and change shape and key.

Global objects, which are hemispheric, are unique in that they have their own field, which is also in the shape of a circle, that affects every object that falls within that field. They typically provide a metronome, or keep time, for any object they affect or act as a tonalizer, correcting notes created by the sound generators and filters.

So how does the system's software turn all of this into music? On the next page, we'll take a look.