MARCO DONNARUMMA

The first DIY version of the XTH Sense was created in 2011 by Marco Donnarumma to investigate exploratory applications of biological sounds, namely muscle sounds, for musical performance and responsive milieux. In 2016, a completely new XTH Sense is being launched to the public. The XTH Sense is used by a steadily growing community of creatives, ranging from performing artists and musicians, to researchers in physiotherapy and prosthetics, and universities and students in diverse fields.

The XTH Sense is open source and open hardware, meaning that its software, the hardware documentation and tutorials to make and use the instrument are freely downloadable on-line. The new version of the XTH Sense is a consumer product, it is wireless and comes with spatial and inertial sensors. It is produced by XTH, a company making open hardware for creative expression, co-founded by Marco Donnarumma and Heidi Boisvert.

The principle underpinning the Xth Sense is not to “interface” the human body to an interactive system, but rather to approach the human body as an actual and complete instrument in itself. Augmented musical instruments and physical computing techniques are generally based on the relation user>controller>system: the performer interacts with a control interface (a physical controller or sensor systems) and modify results and/or rules of a computing system.

Sometimes this approach can constrain, or even drive, the kinetic expression of a performer, leaving less room for her physical energy and non-verbal communication. Besides, because often the sound output of such performances is digitally synthesised, the overall performance may lack of liveness.


The XTH Sense transcends the paradigm of the user interface by capturing sonic matter and control data directly from the performer’s body. There is no apparent mediation between body movements and music because the raw sonic material originates within the fibres of the body, and the sound manipulations are driven by the vibrations of the performer’s muscle tissue.

During a performance muscle movements and blood flow produce subcutaneous mechanical oscillations, which are nothing but low frequency sound waves (mechanomyographic signals or MMG). Two microphone sensors capture the sonic matter created by the performer’s limbs and send it to a computer. This develops an understanding of the performer’s kinetic behaviour by *listening* to the friction of her flesh. Specific gesture, force levels and patterns are identified in real time by the computer; then, according to this information, it manipulates algorithmically the sound of the flesh and diffuses it through a variety of multi-channel sound systems.

The XTH Sense can be played as a traditional musical instrument, for instance, analog sounds can be produced and modified by adequately exciting the “chords” i.e. by contracting the muscles, and it can also be used as a gestural controller to drive audio synthesis or sample processing. The XTH Sense can be used in both modes simultaneously. The most interesting performance feature of such system consists in the possibility to expressively control a multi-layered processing of the MMG audio signal by simply exerting diverse amounts of kinetic energy. For instance, stronger and wider gestures could be analysed and mapped so to generate sharp, higher resonating frequencies coupled with a very short reverb time, whereas weaker and more confined gestures could be deployed to produce gentle, lower resonances with longer reverb time.

The form and color of the music is continuously shaped in real time with a very low latency (measured at 2.5ms), thus the interaction among the perceived sonic force and spatiality of the gesture is neat, transparent and fully expressive. From the exclusive real time processing of the muscle sounds, through sampling of pre-recorded sounds, to the audio manipulation of traditional musical instruments, the XTH Sense is the first musical instrument of its kind to offer such a flexibility at a very low cost and with a free and open technology.