Transducer by Robin Fox and Eugene Ughetti

microphone swinging loudspeakers
Eugene Ughetti swings a axicrophone above his head, whilst three other Speak Percussion members are holding loudspeakers. Video still © Robin Fox & Eugene Ughetti

In Transducer (2013) you might easily recognise all kinds of “classical” playing techniques for microphones and loudspeakers, twisted in surprising and clever ways. This results in a performance which reinvents and expands known pieces such as Steve Reich’s Pendulum Music, Karlheinz Stockhausen’s Mikrophonie I or Gordon Monahan’s Speaker Swinging into unexplored territories. Robin Fox and Eugene Ughetti composed this piece for Speak Percussion (Eugene Ughetti, Matthias Schack-Arnott and Leah Scholes, and guest percussionist Louise Devenish are on stage).

As the title Transducer already implies, this piece is focusing on so-called  transducers: devices that transform one form of energy to another, a category microphones and loudspeakers belong to. The piece starts with a scene which reminds me of the swinging loudspeakers in Gordon Monahan’s Speaker SwingingBut this time a microphone circulates above Eugene’s head, and is, for example, picking up sounds diffused by loudspeakers carried around by  other performers:

One of the main elements on stage is an array of eight microphones hanging above eight small loudspeakers, which remembers us of Steve Reich’s Pendulum Music. Although clearly inspired from the swinging microphones used by Steve Reich, this pendulum-array—containing more and smaller pendulumsis played in a different way, or more accurately: in many different ways. Reich’s Pendulum Music is process-based and acoustic feedback is its sole sound. After releasing the microphones the performers do not interfere anymore with the swinging microphones. The performance is finished as soon as the microphones are hanging stationary above the loudspeakers.

Pendulum Music, Transducer
Eight pendulums of microphones and loudspeakers are played in many different ways during Transducer. Video still © Robin Fox & Eugene Ughetti

In Transducer Robin and Eugene develop an instrumental set-up with the pendulums, which produce many different sounds such as clicks, sine waves or noise. These different type of sounds are generated with the help of patches programmed in the music software Max. The pendulums in Transducer also do not feedback acoustically, but the swinging microphones amplify the sound coming from the loudspeakers underneath them in pulses: the closer the microphone moves to the loudspeaker the louder the sound gets. The signals of the microphones can be amplified through eight bigger loudspeakers placed around the audience.

audience PA
Eight loudspeakers and two subwoofers are placed around the audience during Transducer. (Many other loudspeakers and microphones are placed on stage, see the schedule below for their placement). © Robin Fox & Eugene Ughetti
circuit overview Transducer
This is an overview of all equipment involved during Transducer. (Only the  eight channel loudspeakers placed around the audience are not on this scheme). © Robin Fox & Eugene Ughetti

The whole set-up for Transducer contains many different kinds of microphones and loudspeakers, and therefore a huge amount of possibilities for combining these. Besides the elements mentioned earlier, there are four different tables, all focusing on a specific topic of playing microphones and loudspeakers. On the Textured Table different surfaces are triggering a contact microphone to obtain musical material and have it feeding back through other loudspeakers and microphones. On the Speaker Table a loudspeaker is placed, which membrane moves other objects (including some ping pong balls!), and in fact is acting as a percussionist. The third table is the so-called Mic on Mic table, on which a microphone is amplifying another microphone, which itself is not amplified. The Electromagnetic Table creates sounds with the use of an induction coil and a pulled-open computer.

contact microphone surface
The Textured Table: using  a contact microphone for amplifying several kinds of surfaces. Video still © Robin Fox & Eugene Ughetti
two microphones amplification
The Mic on Mic Table: a microphone is amplifying another microphone, which itself is not amplified. Video still © Robin Fox & Eugene Ughetti

The piece ends with acoustic feedback: Eugene Ughetti approaches two loudspeakers with a microphone. In between them a big tam-tam is placed and starts to resonate according to the frequencies diffused by the loudspeakers placed right behind it. The acoustic feedback is coloured by the resonances of the tam-tam and by moving the microphone close to the tam-tam changes in resonances can be picked up. This might remind you of another well-known composition for microphones as musical instruments. And indeed, the second part of this Speak Percussion concert continues with Mikrophonie I by Karlheinz Stockhausen.

acoustic feedback tam-tam
In this acoustic feedback set-up a tam-tam is placed between microphone and loudspeakers. Video still © Robin Fox & Eugene Ughetti

The whole documentation video of Transducer can be viewed here:

Speaker Feedback Instruments by Lesley Flanigan

Lesley Flanigan Speaker Feedback Instruments
Lesley Flanigan performing with her speaker feedback instruments at La Sala. © Lesley Flanigan

A beautiful example of combining acoustic feedback and musical instruments are the speaker feedback instruments by Lesley Flanigan.  What makes the technology of these instruments exceptional, is their use of so-called contact microphones (simple piezo-ceramic elements) instead of a microphone designed for picking up air pressure waves. These microphones  can easily amplify the mechanical vibrations of objects such as the sound board of a piano, an apple box, or a coffee cooker, without picking up the sonic vibrations of the air surrounding these objects. Or, simply speaking, when a contact microphone is connected to a table, and you are hitting the table and singing at the same time, the contact microphone will only amplify your voice.

In Lesley’s instruments though, these piezo-ceramic contact microphones are placed above the loudspeaker cone, without touching it. Surprisingly, they are in this case used for picking up air pressure vibrations. And indeed, feedback happens with this set-up because the air pressure waves emitted by the loudspeaker are strong enough to be picked up by the piezo-ceramic element and send back to the loudspeaker.  Due to their materiality the frequency response of these piezo-ceramic microphones will filter the sound quite heavily, and it is possible to create a very variable feedback sounds in just changing the distance between microphone and loudspeaker slightly. She discovered this set-up when trying out an amplifier:

I had built a small amplifying circuit, and to test it, I grabbed a couple items that happened to be on my table: a raw speaker cone for the output and a piezo element (basically, a microphone) for the input. The speaker and piezo were touching each other, and a very complex, tonal noise of feedback occurred (Lesley Flanagan in an interview by Tyler Miller).

contact microphone piezo ceramic speaker feedback
A piezo-ceramic element (often called contact microphone) is placed above the loudspeaker cone. © Lesley Flanigan

Since 2007 she has developed several of these speaker feedback instruments, and a speaker synth, which contains of five small different loudspeakers. Lesley told me, that she changes the set ups depending on what she feel works best for the show she is doing (or how far she needs to travel!), but definitely she has her favorites and tend to prefer playing with four at a time.

What inspired her, was that “The sounds of feedback they generated were so “real”—it was electronic sound that I could see and touch.” (Interview by Tyler Miller). It is especially this tactile element which becomes important in playing her instruments and developing her sounds. As can be seen from the video of the speaker synth both contact microphones and the membranes of the loudspeakers are touched to modify the feedback sounds. Each feedback circuit can be turned on and off, and a potentiometer next to the switch can be used for changing the feedback gain:

loudspeaker cones contact microphones
Several speaker feedback instruments made from very different loudspeaker cones taken out of old devices. © Lesley Flanigan

Her instruments are made from old loudspeakers. She is taking them out of devices, because she is interested in not finding a “perfect” loudspeaker but in the specific voice every loudspeaker has. When she heard these speaker feedback instruments “singing”, it felt just very natural for her to add her voice to them. In her performance set-up she literally shares her microphone with them, moving it from her mouth, to the speaker feedback instrument she wants to amplify through the PA system.

For me, it is a special process to collect their raw sounds with a microphone, and amplify them on a large scale. I love the moment when what was once a crusty little noise becomes a booming, warm bass swell of dense tonality. The sound itself never changed, but when amplified, its barely audible details are magnified, so we have the opportunity to hear it differently. By amplifying feedback tones, I’m trying to dig deeper and more introspectively into their sound (Lesley Flanagan in an interview by Rena Minegishi).

In these short fragments of her performances, you can recognise well how the sound of a speaker feedback instrument is amplified as soon as the microphone is approaching it:

As Lesley told me, also this bigger amplification system becomes a part of her instrumental set-up:  “I use a PA for amplification, but often like moving back and forth between the large PA amplified sound and the ‘acoustic’ sound of the feedback instruments without any amplification.” During her performances, she develops different layers of feedback and voice, using a looping pedal for sampling sounds. Whereas they are carefully prepared and rehearsed, and she clearly knows her instruments very well, she is always also reacting on what happens at each specific moment: “I knew which speakers to work with and how to play each one to bring out elements of tonality, noise and rhythm I wanted to hear. The sampling and layering of their sounds were intentionally obvious, methodical and dense. But with all that said, I could have never predicted the exact sounds that would come out of the process. Many variables effect the feedback I work with, so no matter how much control I have planned, improvisation is always at the forefront” (Lesley Flanigan in an interview by Marc Weidenbaum).

 

 

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

Bandoneonbook by Hans W. Koch

Hans W. Koch performing Bandoneonbook for laptop
Hans W. Koch performs Bandoneonbook, using the acoustic feedback between the internal microphone and loudspeaker of the laptop.

In Bandoneonbook (2003) by Hans W. Koch the acoustic feedback between the small internal microphone and loudspeaker of a computer is played by opening and closing the laptop, similar to how one would play a bandoneon. The music software Max (at those times still called MaxMSP) is controlled by the keyboard of the laptop and by pressing some keys the feedback will be filtered in different ways. A piece which can only be performed with a titanium-powerbook series of 2001!