Points of Contact by Erfan Abdi

Erfan Abdi in the bird cage, performing Points of Contact at STEIM.
Erfan Abdi in the bird cage, performing Points of Contact at STEIM. © Erfan Abdi

Big eyes as contact microphones, a bird cage as a loudspeaker, and two double spring objects of which again one functions as a loudspeaker and the other as a loudspeaker: this is the inventive set-up Erfan Abdi uses for his performance Points of Contact (2017). Erfan himself seems to be a bird, placed in the cage to perform for us, gently trying to break out by touching the bars with his metal eyes.

The sounds during the performance are created by different combinations of the same set-up: both amplification as well as feedback through the contact microphones and tactile transducers are used. By using additional long springs the different elements can be connected to each other. To give an example of one of the many possibilities for doing all kinds of physical signal processing with this set-up: a signal of the big eyes contact microphones is sounding through the bird cage transducer, and since both are touching each other a feedback loop occurs (1 in the scheme below). The bird cage is also connected with a spring (2) to the double springs with a contact microphone (3). This is amplified through the transducer attached to two double springs (4). This is fed back again to the double springs with a contact microphone (5) by connecting the springs with the help of again an additional spring. The sound of all contact microphones is also amplified by the two main loudspeakers in the hall (the PA system) (6).

transducer exciter contact mike microphone Erfan Abdi
Set-up scheme for Points of Contact by Erfan Abdi, see the description above for a detailed explanation.

What makes this set-up so versatile for producing all kinds of different sounds, is that the two feedback loops can both be combined, influence each other but also broken up again (the first feedback loop are the contact microphone eyes and bird cage transducer, and the second the springs contact microphone and springs transducer). Take away, for example, the spring in between the two double springs—(5) in the scheme above—and the double springs become a spring reverb for the sound produced by the bird cage feedback. The whole set-up is constructed in search for fragility and inaccuracy in response to the feedback signal. For this reason, the two contact microphone springs have been chosen by Erfan because their frequency response is slightly different: this results in a modulating feedback sound instead of a feedback on one constant pitch.

The two contact microphone eyes
The two contact microphones are enlarged by small metal plates so they can touch several bars of the bird cage at once. © Erfan Abdi

For the same reason the contact microphones eyes are made by simple piezo disks placed on round metal plates: this gives the possibility to touch the bird cage at two or three bars. As Erfan explained me, when there is just one point of contact between the contact microphone eye and a bird cage bar the feedback tends to be especially strong on the fundamental frequency of the pitch. But as soon as you touch two or three of the bird cage bars, more partials are added to the sound. And by using two contact microphone eyes they also start to modulate each other. The placement of the contact microphone below the  two springs is again aiming for a richer and less stable sound: instead of having just a single point of contact, the whole disk is touching as much as possible of the surface of both springs.

The contact microphone beneath the springs. © Erfan Abdi
The contact microphone beneath the springs. © Erfan Abdi
The contact microphone beneath the springs. exciter body shaker
The tactile transducer underneath the two other springs. © Erfan Abdi
The tactile transducer bird cage exciter body shaker
The tactile transducer attached to the bird cage. © Erfan Abdi

Erfan uses the music software Reason to do some processing of the feedback. Basically it provides a compressor, a delay line and an amplitude follower. The amplitude follower is used for modulating the delay time, so as soon as one frequency gets too loud, the delay is changed, and the frequency of the feedback will also change. The connections between the different parts of the set-up—which contact microphone is connected to which transducer etcetera—is controlled live by Erfan with a small MIDI controller.

During the performance Erfan is sitting in the cage, an intriguing image for a music performance. The movements of his head towards the thin cage bars seem to underline the scenery of a bird locked in against his will. But it is with the resulting sounds that this bird seems to be able to leave the cage: the variety of sounds not only enlarge the musical possibilities of this set-up, but also give the impression that the music can sonically fly away from the cage. The bird might seem to be locked in visually but sonically it is free to come and go.

Below you can view some short fragments of Erfan Abdi performing Points of Contact at STEIM in Amsterdam, and listening to a recording of a performance excerpt. And if you are close to The Hague: Erfan performs a new version of this piece tomorrow (Thursday 10th of October) at Ephémère at Studio LOOS.

Vestiges of Discomposition and other works by Simon Whetham

loudspeaker earth water Simon Whetham
Loudspeaker covered with earth during Simon Whetham’s performance Vestiges of Discomposition. © Simon Whetham

Before Simon Whetham starts his performance, he asks you to close your eyes. However, I could not withstand to open my eyes briefly once in a while. I saw Simon walking around slowly, holding a cymbal in his hands. A tactile transducer was attached to the cymbal (Simon uses Dayton transducers, often also called exciters. If you want to know more, about what kind of microphones and loudspeakers he is using, have a look at the very detailed equipment list on his website). Larger sounds were diffused by a tactile transducer attached to the big metal ventilation system on the ceiling, resonating in different ways depending on the frequencies diffused by the tactile transducer.

tactile transducer ventilation system
The tactile transducer attached to the ventilation system. © Simon Whetham
Simon Whetham object tactile transducer
Simon Whetham is carrying an object with a tactile transducer attached to it through the audience. © Simon Whetham.

Every performance space is different of course, as are the objects you might find in such a space, so I asked Simon how he prepares for these performances. He answered me, that besides being experienced enough now to often know already what object might sound good, “banging and knocking on objects to test their resonance and which part is more resonant is essential. Also when setting up I will place objects in various parts of the room to test how each one works in the space, for distance and if they will even vibrate against another resonant object. But then this can change during the performance as I often have no control over where people sit!” And some of his favourite objects, such as the cymbal, just travel with him.

cymbal tactile transducer Simon Whetham
Simon Whetham holding a cymbal with a tactile transducer attached to it during the blurred edges festival 2016. © Simon Whetham.

As an input Simon uses pre-recorded sounds and recordings made in the performance space itself, but also produces many sounds live. For creating live sounds he often uses a small loudspeaker cone,“I also started working with an open speaker as a sound source, either by playing audible sounds through it and then channeling them around the room, or using inaudible low frequency recordings and placing objects inside the speaker. I like this approach as field recorded low frequencies are often unpredictable in their volume level, creating an erratic ‘rhythm’ with the objects in the speaker or even throwing them out.”

aluminium foil loudspeaker Simon Whetham
A loudspeaker cone prepared with broken glass. © Simon Whetham. Picture by Michel Pennec of humus in Lausanne.

As a result of sending the same recorded sound to the differently prepared loudspeakers in space, there are now several representations in the room: one is the sound of the loudspeaker cone covered with, for example, broken glass or stones, the other ones are very similar sounds somewhere else in the space, but filtered by the spectral characteristics of this object. You hear beautiful reminiscences of sounds of scraping stones, scratching metal, or the electric noise made by a ventilation system. But all of them are surrounded by a sonic aura, which makes them less recognisable, transforming them into more imaginary sounds, not related to any existing things. Listening to a recording can of course never reproduce such a performance, but it might give you at least an impression of what kinds of sounds were used:

In contrast, in Everyday Emanations (Dead End) (2017) the sound source is more easily recognisable and plenty of visual cues reveal the source of the sound. Once again, Simon uses tactile transducers, this time attached to damaged car parts. He recorded sounds of traffic inside objects such as pipes, bottles and cans in the streets of Nakanojo (Japan) and these are played through the tactile transducers. Or in Simon’s words: “So ‘dead’ cars would play the sounds of ‘live’ ones.” This time your eyes should not be shut, since car lamps are used to light the space, turning on and off according to the volume of the sound.

An even more direct examination of the physicality of sounds occurs when Simon uses loudspeakers for creating physical marks. The visuality of the performance—completely absent during the first performance I discussed—plays a crucial role now. Simon mentions the book Lines: A Brief History by Tim Ingold to explain more about these works: “Ingold describes two classifications of lines – threads and traces. I was led to consider traces of sound, or of action that makes sound. This ranged from retracing grooves cut into metal objects by the process of twine production, to actually creating physical traces of sounds, to be displayed as visual representations.” In Trace of Water (2016) several metal wires are attached to a very small loudspeaker. A recording of cascading stream water in Wongol (South Korea) is carrying the loudspeaker through the sand, literally leaving its traces in the sand:

Another work using also the sounds of cascades is the very poetic Vestiges of Discomposition (2016), developed on Mount Tsukuba in Japan. Simon used hydrophones to supply a live sound feed, “carefully positioning it to pick up the most energy from the flow. When transduced to sound through a speaker, this energy manifests itself as a low frequency that is unheard by human ears, but creates a strong movement in the speaker itself.” He now fills the different loudspeakers with earth and water, recreating the landscape the loudspeakers are placed in. “These ‘landforms’ mark every point where the stream makes more audible sound above the water, therefore acting as listening stations.”

In Trace of the Storm (2017), created of the Open Arts Project in Busan (South Korea) a recording of a storm is played through two loudspeakers. One of them is a loudspeaker attached to the wood of a painting, the other one is a speaker cone filled with Korean ink, and producing a similar painting as the first one. “The sound continues to play through both pieces, but is heard in two different ways. The picture filters out low frequencies so you hear more detail, whereas the open speaker is almost inaudible, but creates another ‘drawing’.” This results in what could be called an action painting by a loudspeaker. In Simon Whetham’s works the microphones and loudspeakers are not only transducing between air and electricity, but they translate between all kinds of movements and sounds.

The trace of the storm by Simon Whetham
The trace of the storm by Simon Whetham: one finished painting and one in the process of making. © Simon Whetham.

Fifty years of loudspeakers and ping pong balls

Some objects seem particularly suitable to be used for preparing loudspeakers. The lightness and characteristic sound of ping pong balls might be a reason, why they have been favourable objects for this. Comparing several of these set-ups reveals that—fortunately!—using a similar technology can still result in completely different works.

Loudspeakers ping pong balls
Leser 1 by Manfred Mohr and Jochen Gerz. The loudspeakers and ping pong balls are covered by a large transparent plastic bag. Polyester tube, 19 loudspeakers,  printed transparent plastic bag, 19 moving ping pong balls, electric motor, 180 cm x 45 cm, 1967 Source: www.emohr.com/collab-exp/col_mohr-gerz.html © Manfred Mohr and Jochen Herz

As far as I know, the first work using ping pong balls in combination with loudspeakers is Leser 1 (1967) by Manfred Mohr, who created the audio sculpture, and Jochen Gerz, who wrote the text for this installation. This  tower contains 19 loudspeakers, each prepared with a single ping pong ball and was exhibited for the first time in 1968 in Paris. The audience can press a foot pedal to turn the installation on for a minute. Three different frequencies are then played through the loudspeakers and causing the ping pong balls to move away from the loudspeaker membranes and hit the plastic bag (see also the scheme at the end of this post). The ping pong balls are alternating between striking the plastic bag and the loudspeaker membrane and the combination of 19 ping pong balls making this movement produces a noisy sound. Together with the text printed on the big plastic bag and a random letter printed on each ping pong ball the whole installation seems to make an attempt to speak. The text itself seems also to be related to the movement of the ping pong balls: the big letters in the middle read: “Auf Flüchtlinge wird [ge]schossen”, which could be translated as “shoot the people fleeing”. Manfred Mohr explained me, that this text refers to the fact that at that time the East German police had the order to shoot the people fleeing to West Germany.

In Music for Pure Waves, Bass Drums and Acoustic Pendulums (1980) Alvin Lucier uses four bass drums and places them in front of four loudspeakers. A low sinus sweep is played through these loudspeakers and the membranes of the bass drums start to vibrate, according to their resonance to the frequency of the sinus wave. In front of each drum a ping pong ball is hanging from the ceiling, just touching the drum head. The vibrations of the skin push the ping pong ball away from the drum. Depending of the moment of hitting the drum, when the ball falls back, as well as the direction and amount of vibrations of the drum head, the ping pong ball will be pushed away next time with more or less force. Although the set-up seems to be four times the same, the results of the small differences in material of bass drum, loudspeaker and ping pong ball can be clearly perceived in the movement of the ping pong balls and the resulting sound. The shape of the ping pong balls reminds me of the head of a drum stick, and these drums seem mysteriously “played” by the ping pong balls.

Christian Skjødt uses 16 loudspeakers and an equal amount of ping pong balls in Inclinations (2016). Here again each loudspeaker with ping pong ball combination creates its own rhythm, but due to the ping pong balls moving in upwards direction they fall down much faster than in Lucier’s set-up. This causes a constantly changing, soft and noisy rumbling. Christian is not using any other material such as a plastic bag or drums. Since the frequencies played through the loudspeakers are too low for humans to be heard, all sound is produced by the collisions of ping pong balls and loudspeaker membranes. The minimal visual quality of this installation underlines the focus on these sonic events.

loudspeakers ping pong balls
The three different relationships between ping pong balls and loudspeakers, from left to right: In Leser 1 the ping pong ball hits the loudspeaker and the transparent plastic bag. In Music for Music for Pure Waves, Bass Drums and Acoustic Pendulums the loudspeaker just hits the drums. In Inclinations the ping pong ball is placed directly on the loudspeaker.

After I finished this post on loudspeakers and ping pong balls, Ricardo Arias brought the piece PingRoll (1997) by Manuel Rocha Iturbide to my attention:

And João Ricardo mentioned Kugel-Percussion (2006) by Peter Vogel to me:

loudspeaker ping pong ball
Kugel-Percussion by Peter Vogel, with one ping pong ball and one loudspeaker © Peter Vogel

And another addition: When preparing my text on Sound in a Jar I bumped into another piece of Ronald Boersen, using loudspeakers and ping pong balls, called talk to me… . The ping pong balls are hanging in front of a tam-tam . You talk into a microphone and see and hear your speech reflected in the movement of the ping pong balls. To achieve this, the voice is processed in the computer, attenuating resonating quality in the speech, that maximises the response of the resonating frequencies of the tam-tam. This sound is than diffused through a tactile transducer attached to the tam-tam. The ping pong balls start to move due to the tam-tam vibrations, creating sounds themselves as soon as they hit the tam-tam:

Doppelbelichtung by Carola Bauckholt

Carola Bauckholt has written several pieces in which the imitation of bird sounds plays an important role. Examples are Lichtung (2011) for string quartet and Zugvögel (2011/2012) for five wind instruments. In her piece Doppelbelichtung (2016) for the first time these “photographic imitations”—as Carola calls them—are confronted with real recordings of singing birds. This piece is for violin and 12 loudspeakers, among them several “violin loudspeakers”: by placing tactile transducers on violins and hanging them in the concert hall, sounds are transmitted through the corpuses of violins.

A tactile transducer violin ceiling
A tactile transducer attached to a violin, hanging from the ceiling. © Carola Bauckholt

Carola brought both worlds of violins and birds together in this composition and both have to be transformed to be able to approach each other. To imitate the bird songs, it is necessary that the violinist listens very carefully to the birds and searches for appropriate playing techniques to be able to imitate the birds as good as possible. But also the birds have to move closer to the violin:  their songs are slowed down, resulting in lower and slower songs. Both bird and violin sounds are notated very precisely in the score:

score Doppelbelichtung Carola Bauckholt
A fragment of the score of Doppelbelichtung by Carola Bauckholt. All bird names as well as the speed change of the recording are notated. © Carola Bauckholt

The twelve audio tracks of transformed bird recordings are played through twelve loudspeakers. Two of these loudspeakers are normal PA loudspeakers. Four of them are small loudspeakers placed in the audience, another small one is used as a monitor for the violinist. Most remarkable are the five “violin loudspeakers”, as mentioned above these violins have tactile transducers attached to them and the audio is sounding through the violin.

set-up violin loudspeakers Carola Bauckholt Doppelbelichtung
An overview of the set-up for Doppelbelichtung with the five violin loudspeakers (violin loudspeaker 5 is playing Specht sounds, which is a woodpecker). © Michael Acker, SWR Experimentalstudio
Violin loudspeakers Carola Bauckholt
The set-up in the concert hall, with the hanging violins, the PA loudspeakers on stage behind the violinist Karin Hellqvist and the small loudspeakers (the metallic objects next to Karin Hellqvist belong to another piece). © Carola Bauckholt

Double exposure—the english translation of the title Doppelbelichtung—is the technique of taking two pictures on one frame of film. In this piece every sound seems to be a sonic double exposure of a violin and a bird: the violin is imitating the bird sounds, which are in turn modified to resemble the violin. By transmitting these sounds through tactile transducers attached to violin corpuses hanging in the air every bird recording acquires spectral characteristics of a violin. The piece is a thoughtful conversation between these new creatures.

Doppelbelichtung has been performed by Karin Hellqvist and the SWR Experimental Studio: