Tonewood by Hugo Morales Murguía

Tonewood Hugo Morales
A tactile transducer as used in the Tonewood pieces: 2 cm cork on top, and some felt to not harm the instrument. © Hugo Morales Murguía

Tonewood I (2011) and Tonewood II (2015) by Hugo Morales Murguía are using small tactile transducers with corks attached to their cone. Five musicians play their instruments with these transducers. The transducers are not sounding at all, as long as they are not pressed to any surface. During Tonewood they are pressed against the wood of the soundboards of violins, guitars, violas, violoncellos, double basses or pianos. In this way, their soundboards become a kind of membrane for the transducers. As Hugo describes in the score:

The term “tonewood” generally refers to any wood which may be used in the construction of a musical instrument, specifically string instruments. An intrinsic characteristic of these instruments is the use of a resonant chamber, or sound-box, which not only projects the sound of the instrument but provides personality and quality to the overall sound of the instrument depending on its size, architecture and different kinds of wood used in its elaboration. This piece explores the internal resonances of each instrument and the way these correlate with the external performance space. For this, each instrument is continuously “scanned” through a series of impulses, exciting several resonant modes and projecting different overtones resulting in complex harmonic relationships.

Score Tonewood Hugo Morales
At the beginning of the piece the instruments slowly fade in. © Hugo Morales Murguía

Very minimal material is diffused through the transducers: just a pulse repeated each 80 ms and a sine wave of 659 Hz (pitch e). These are generated by the music software Max. To scan their instruments the musicians follow a score in which three different aspects are notated. First of all, the volume of the sound diffused by the transducer (thus being the volume of the 80 ms clicks or the 659 Hz). They control this with a volume pedal. The second aspect is the amount of pressure the player uses to push the transducer against the instrument: low pressure, normal pressure and overpressure are the indications mentioned in the score. The last aspect is the placement of the transducer on the instrument, which is indicated by 4 (Tonewood I) or 9 (Tonewood II) numbers.

tonewood Hugo Morales
The nine different spots used for pressing the transducer against the instrument in Tonewood II. © Hugo Morales Murguía

This piece is not played on the strings of the instruments and neither fingers nor bow movements are producing the sounds. For this reason, the five musicians playing this piece turn their instruments around. This allows them to easier access the soundboard of their string instruments.

Ensemble Vortex rehearsal Tonewood Hugo Morales
Double bass player Jocelyn Rudasigwa during a rehearsal of Ensemble Vortex: she has turned her double bass around and is scanning her instrument with a transducer.
Tonewood Hugo Morales
Tonewood II starts with quick changes between normal pressure and overpressure,  a crescendo of the pulses controlled with the volume pedal and the transducer placed on the middle of the instrument. © Hugo Morales Murguía

This is a video documentation of Tonewood I performed by ensemble Modelo62 . Just having the same pulse repeated till nearly the very end of the piece opens your ears for a miniature world of sonic changes, all caused by the resonating bodies of the instruments themselves.

The system of Hugo reminds me a little bit of Ute Wassermann’s Windy Gong, for which she uses a loudspeaker with a cork placed on top. And indeed: Hugo confirmed me that he had been influenced by Wassermann’s loudspeaker after reading about it in Nicolas Collin‘s great book Handmade Electronic Music. This is—by the way—an indispensable book not only for those interested in hardware hacking in general, but also for several hands-on microphone and loudspeaker technologies. Chapters such as How to make a contact mike, The celebrated jumping speaker of bowers county, or Turn your tiny wall into a speaker are great sources of inspiration.

Tone wood II is going to be performed on the 30th of March in Geneva, so if you are close by, you can attend the concert by Ensemble Vortex during the Archipel Festival.

A sympathetic piano by Gökhan Deneç

The electromagnets attached 2 mm. above the piano strings to create a sympathetic piano. © Gökhan Deneç

In Chapter Three of my book I discussed several early attempts of creating electric piano’s during the end of the nineteenth century. Often these efforts made use of electromagnets and feedback to keep the piano strings in vibration. The Neo Bechstein was one of the first commercially available results, but did not use any feedback anymore. During recent years new compositions and systems using electromagnets or tactile transducers and feedback for sound shaping and diffusing have been developed, for example by Per Blond, Andrew McPherson and Rama Gottfried (I’ll post about them in the future). Also Wave Train (1966) by David Behrman is related to these kinds of electric piano’s.

The hand-wounded electromagnets, with the permanent magnets inside the plastic reel.
The hand-wounded electromagnets, with the permanent magnets inside the plastic reel. © Gökhan Deneç

Gökhan Deneç has developed a sympathetic resonance system for a piano using electromagnets and feedback through its strings. He developed his own hand-wound transducers for this, using a simple but effective combination of wire, magnets and plastic reels. These electromagnets are placed in a grand piano and hung approximately 2 mm above the strings. The piano strings are attracted and repelled by the magnetic fields caused by these electromagnets. By sending the same signal through all electromagnets each piano string will start to vibrate, depending on how much its partial tones relate to the spectrum of the signal sent through the electromagnets.  A contact microphone (a model similar to an AKG C-411) is attached to the soundboard of the piano. In between this microphone and array of electromagnets a Pure Data patch is controlling and shaping the signal to the electromagnets. As Gökhan explains:

”My first intention was to create feedback to excite the piano strings and then by manipulating it I would create textures. Then I decided to define some possible regions for feedback to occur by sending an initial sound and also accompany the feedback by these textures. Also, I have a filtering algorithm that keeps the feedback under control. […] The sound creation is realised in PureData; there is a generative algorithm that I designed to create a very specific type of sound world. […] What you hear in the video is the generated tones that are created to vibrate the piano strings and because of its nature, they are unique in their own time. I can not repeat the same sounds, there are tons of randomization going on to construct this generativeness.”

This sound processing is controlled by the amplitude of the feedback signal coming from the contact microphone. Gökhan created an algorithm which is generating clusters of ten pitches, relating to the number of our fingers. A detailed explanation about how this all functions can be found in his PhD research. His PhD is entitled Creating sound mass using live sound processing and feedback with sympathetic vibrating strings and was defended in 2015 at Istanbul Technical University.

Gökhan Deneç is continually developing this project, so if you are a composer or sound designer interested in this system and would like to experiment or even compose a piece for this, please feel invited to contact him!

The Pure Data patch with a ten pitch cluster.
The Pure Data patch with a ten pitch cluster. © Gökhan Deneç