Hybrid instrument into micro-bioacoustic

Updated: Jan 13

To investigate a method which the electronic sound generated is translated by transducer into a light membrane diffuser is the chosen method into this research. That approach is called hybrid, where you approach the analogue difusion of the electronic sound signal, exploring the mix between digital and analogue acoustic possibilities and aiming to reach a new range of possibilities, range and colors of sound distribution. A hybrid application was also part of most previous electric cello's research at MIT by Tod Machover, a investigation of hyperinstruments research group in 1986 and a stringless cello in 2005, at CNMAT under the UC Berkeley Regents Lectureship Program, with David Wessel, Adrian Freed and Michael Zbyszynski. Yo yo ma and Frances Marie Uitti helped and contributed (respectively) to those researches giving an ergonomic and practical overview to those prototypes:


Fig. X : http://fab.cba.mit.edu/classes/863.10/people/adam.setapen/finalProject/

There is a small difference between Hybrid and Augmented instrument. Respectively, one allows a combination between acoustic and electronic sound while Augmented aims to enlarge musical possibilities only by digital music streaming. Both means to extend musical possibilities of an instrument by digital sound. As with cellos, It has been developed researches with Pianos, Orgel, Violin, Guitar and Drums, wind-instruments. Although, 'there is no necessity to maintain such a distinction between acoustic, electronic and digital instruments. Analogue systems are used in any machine mechanism, which makes us totally confused to define why a piano is considered as a acoustical instrument' (MAGNUSSON, 20). The way that you approach and stream a sound data it is how we differentiate those systems.

Hybrid instruments started to couple the speaker into the sound box. Both are in theory opposite by its propose: a speaker box is designed to not resonate with the vibration of the transducer, meanwhile the soundbox is a surface aimed to compress air and forces in a way that the sound could be streamed. Some experiments with Ircam with guitar and cello started in the early of 80's proved that it could be a great challenge, but a successful approach. As Eldridge defines into her NIME article, the speaker and to be attached with a mounted on a spruce collar to maximise vibrational conductance.


Fig.x : A 50W speaker is built into the back of the cello body.

Besides the physical space, the main problem into bring a hybrid approach on cello or other acoustical instrument is feedback. Halldór, the creator of recently Halldorophone, transformed this problematic into it's favor, allowing it to be a feature of coloring and generating sound.


Fig.x: Halldorophone (http://www.halldorophone.info/) made by Halldór Úlfarsson

As architecture seeks, to ensemble its member parts giving different functionalities could also allow both goals of sound propagation (vibration and filtering) to work together. Active acoustics is a recent concept that investigate and research mechanisms of absorption and diffusion for acoustic propagation. It facilitates the combination between acoustic and electronic distribution avoiding or welcoming feedback signal.

A curious acoustic research from the Ghent's making instruments' department prove that mycro air-cavities from Styrofoam material could result a more powerful diffusion and therefore, a better sound quality, as a conventional cello produces. 'Styrofoam has a closed cell structure which doesn’t allow sound waves to enter it easily and be absorbed so, instead, the sound is amplified' (MAKENZIE).


Fig. x: Tim Duerinck's project of a Styrofoam cello (cellist:)

This would be an unconventional acoustic approach where the air cavity, the resonance chamber, the air nodes and turned apart in microscales. When it is pressed or stressed, styrofoam could induce an equal ratio sound distribution.

Nowadays polystyrene (styrofoam) and composites material its possible to exchange it by an better environmental-friendly material, mycelium, a fungus subtract that works as glue when it grows:


Fig.x : Comparing Mycelium and polystyrene (Styrofoam) in a microscopic view, we could observe the air nodes

As styrofoam or cork, Mycelium has the potential to induce sound through air, reaching up to 70dB on its source. Like as the styrofoam cello experiment, sound waves produced by the vibrations of the cello strings were magnified by the closed cell structure of the polystyrene foam, producing greater volume with less effort and a more prominent bass register.

Hybrid instruments is a recent research, transforming old formats into new necessities. They are no previous tentatives about about active acoustic into hybrid instruments. Therefore that's what we are interested to investigate, relating the design with a compositional approach explore on the coming chapter.