Cello

2001-2002 a project by Beatriz da Costa

Cello is a robotic sound installation, which combines autonomous behavior with interaction. The piece concerns itself with the act of learning, performing and adapting oneself to external pressures. Cello consists of an automated acoustic cello that alters its behavior in response to computer generated sine wave tones and to the position of visitors in the space. The cello tunes itself. String after string tightens and loosens slowly on motorized pegs, while being bowed and compared to the sine wave tones emitted by a speaker. A pick-up microphone transmits the cello frequencies to the computer program, in which their relationship to the "right" frequencies is evaluated. The pegs, in response will turn in one direction or the other until each string is declared to be in tune.

Once the cello has approximated the goal of self-tuning, it performs a set of simple phrases by manipulating and adjusting its own bodily elements. The cello advances slowly from phrase to phrase, observed by the program and compared to a predefined sequence. Each phrase is repeated until it has been correctly performed before advancing to the next one. However, the physical predisposition of the instrument does not allow it to ever fully meet the expectation of a perfectly executed musical performance. To complicate matters further, if approached by a visitor too closely, the cello interrupts its current behavior (tuning or playing) and performs a random "irritated" behavior. If provoked over a long time, it eventually "untunes" itself and reverts back to its starting point. Once left alone the cello begins to retune itself and attempts to perform again.

Cello uses robotic technology in combination with an analog acoustic instrument--a paradox in itself. Tactile instruments (amplified electronic or fully acoustic) are traditionally played by human beings and are designed to unveil their acoustic properties under the hand, arm, feet and breathing motions of humans. Human musical performance is a fully embodied activity, and requires a highly specialized coordination between the motor system and the senses. While there has been a history of automated mechanical instruments such as player pianos, and early century musical automata, a technological structure has not been created that can fully replace human presence in the musical performance process. In addition, Cello is a part of the instrument-family that is the hardest to mechanize and automate. Cello not only addresses the history of human desire to replace and extend human activities with machinery and the importance of embodiment within intelligent systems, but incorporates both of these subject areas in an interactive metaphorical narrative, performed by a computer, a cello, a speaker and the visitors.