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:

 

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.