s_platters: spinning platters for audio control

s_platters is a controller for electronic audio production, created by Freida Abtan at Brown University. The system uses magnets, hall sensors, gyroscopes, and capacitance sensors to track the momentum, position and manipulation of three spinning platters. Inertia and friction are naturally incorporated into these values. Each platter smoothes and conditions its own data before sending it via a wireless network to custom software for statistical processing. Software audio instruments use the generated values to make music.

The construction of the controller encourages multiple kinds of human gestures, such as gentle lateral pushes towards a platter’s rotational spin, or resistance force applied from above. The long smooth rotations of the platters, arise as much through their natural physics as from significant human effort. Effort is used when making small changes to platter motion, or when opposing the physical forces acting on the platters. Variations in the speed and direction of platter manipulation are points of control for the instrument’s musical output, as is touch, or close proximity.

The controller is capable of endless mappings to software instruments. In performance, it is commonly used for polyphonic playback of at least two, and often three, voices. One voice can be controlled by a single platter’s movements or it can respond to the manipulations of several. Further, correlated gestures between platters have an excitation effect on the software system. The gestures with which the platters are manipulated, control both the textural quality of sounds produced as well as their dynamic shape. Several software instruments can be combined into an open composition, in order to keep things varied during a live performance. Some software instruments already developed for s_platters include: granulation process according to a combination of momentum and rotation, granulation overlap process according to rotation, scrub sample playback according to momentum and rotation, resampling, banks of filters and delays according to touch and/or rotation, fm synthesis according to touch timing and rate of rotational change, and pattern creation based on rotation and touch.