The sonic palette for ZiZi the Affectionate Couch was designed to attract people to sit and stroke her so that she would purr. It was also designed to provide a feeling of an affectionate response. An analysis of the design has led to a method for designing Affective Sounds for Interactive Commodities.
Barrass, S. (2012) ZiZi the Affectionate Couch and the Interactive Affect Design Diagram, in K. Franinovic & S. Serafin, Sonic Interaction Design: Fresh Perspectives, MIT Press. (April 2012).
The palette was limited by the custom-made hardware to sixteen short mono audio files. This limited palette is mixed through a four channel sound system to produce a dynamic and ever changing stream of sounds in response to interactions sensed by a motion detector inside the couch.
The design process was a series of iterative prototypes that explored sonic characters such as a cat, a dog, a bird, a dolphin, and an abstract appliance creature that beeped like a microwave. The final palette of sixteen ZiZi sounds contains a mix of whistles, mews and yowls that does not specify a particular animal. Through the design process the sounds became classified into groups around phases of interaction :
1) attract attention. The attention attracting sounds were short (1/2 second) and high pitched.
2) upon sitting. The sitting sounds were slightly longer (1 seconds) with sharp atttack to produce a haptic quiver as well.
3) encourage patting. The patting sounds were more sustained (2 seconds) with a more regular pattern of vibration.
4) produce haptic purring. The final purring sounds were longer still and more even to activate haptic purring effects from the vibrators.