Ping Roll excerpt


 

PING ROLL 1997

pingroll video on youtube

Ping Roll. Biennale of Sidney Australia. September 1998.

 

This sound sculpture has 3 series of speakers that play 3 tracks with the sound of processes of Ping-Pong balls bouncing stochastically, alternating with periods of silence, and with pure sinusoidal frequencies. The sound of each track alternates between each other so that the speakers sound at different times. The sinusoidal frequencies diffused through the speakers were calculated in order to be sympathetic to the natural tuning of the sculpture’s aluminum plate, so that they make it vibrate and resonate. The effect of the vibrating plate over the Ping-Pong balls is that some of them bounce in a fixed point, while others get out of their bouncing orbit and slide through the surface of the plate.

The primordial function of a Ping-Pong ball is to bounce -a discontinuous movement-, but the law of gravity could make a ball to bounce every time faster, and eventually to produce tone frequencies -a continuous movement-. Metaphorically, the fact that the continuous sinusoidal tones causes the real balls to bounce or roll over the plate, while the actual sound of discontinuous bouncing produces stasis, represents a sort of paradox where the two opposite states of the ball, the discontinuous (bouncing) and the continuous (rolling) are in reality both part of one same phenomena. This metaphor is related to the quantum theory where light can behave either as particles (discontinuity) or as waves (continuity). Acoustically speaking, the discontinuous bouncing represents rhythm and the fast bouncing represents frequency. We have in this way a dialectic or game of opposite states generated by these two essential elements of sound.

The duration of the sound sequences corresponds to the structure of the logarithmic bouncing of a Ping-Pong ball while we drop it over a hard surface. The ball bounces every time faster affected by the laws of gravity and friction. I used a constant ratio (.666) [1] related to the golden mean, as a multiplying factor that decreases the duration’s of the bouncing sounds, of the silences, and of the sinusoidal frequencies [2]; there is also a progression where the bouncing sounds start with a slow rate and get every time faster, and where the sinusoidal tones start with very low frequencies and then increase gradually in frequency. At one point of the process, there isn’t any more silence between the sounds, and they start to overlap, arriving to a climax zone made out from fast bouncing sounds and high sinusoidal frequencies. After this climax there is a backwards mirror of the process where the sounds and silences start to get longer again. The whole process lasts for 38 minutes and 15 seconds.

Besides the dialog established between discontinuous and continuous movement, the sound sculpture itself is a sort of chaotic game. We start the game by spreading all the balls over the table homogeneously and equidistant one from each other. This is a very improbable ordered state. The balls will then start to move and will tend to go to certain zones of the table which I call entropy zones, because the balls move less and less every time, and after a little while they always stay near this zones. We have here an example of the chaotic phenomena of "sensitive dependence on initial conditions". Amazingly, the different configurations formed by the movement of the balls will vary greatly even if we have at the beginning exactly the same volume level, and the same starting positions for the balls. At the end of the whole process, we have to spread the balls again equidistantly and wait to see a new entropy process that will go from order to chaos.

 

 

 

 

Detail of balls distributed in a chaotic way over the table

 

1. - On reality, the ratio of the decreasing durations is not constant in the real bouncing process. I measured the decreasing rhythm of a ping pong-ball bouncing and verified this. The logarithmic ratio started at .8 but it increased gradually op to .94. On the other hand, I decided to use a fixed ratio to give a fractal structure to the whole structure, and I used a lower ratio (.666) for musical purposes, because the process of diminishing duration’s runs faster and is more easily perceived.

2. - Each new duration value is always multiplied by .666. For example, if we start with 180 seconds for a bouncing sound, in the next step, this bouncing sound will be reduced by 180 * .666 = 119 seconds, then 119 seconds is again multiplied by .666, and so on.

 

 

 

Ping Roll. Biennale of Sydney Australia, September 1998


PING ROLL 1997

Esta escultura sonora consta de una plancha rectangular con bordes, hecha de laminas delgadas de metal y montada sobre cuatro patas. Es decir, una especie de mesa, como si se tratara de un juego. Sobre esta plancha se encuentran de 30 a 50 pelotas de ping pong, y en la base inferior de la plancha hay 6 bocinas pegadas distribuidas de manera equidistante a lo largo y a lo ancho. Las bocinas están conectadas a 3 CD estereo. Cada CD tiene grabadas dos pistas con el ruido del rebote de una pelota de ping pong que se acelera hasta convertirse en una frecuencia; el principio acustico de una repeticion rápida contínua produce un número determinado de periodos por segundo, equivalentes a una frecuencia específica. Por ejemplo, 100 rebortes por segundo equivale a una frecuencia de 100 Hz, aproximadamente un sol#. El sonido grabado en cada pista efectuará un proceso entre rebotes discontínuos y rebotes contínuos, llegando cada uno a una frecuencia diferente. Los procesos de los rebotes estarán alternados con silencios, de manera que las 6 bocinas casi nunca sonarán al mismo tiempo. Como pienso usar 3 CD's grabados, puedo utilizar la función random de los reproductores de CD para que exista un factor aleatorio que afecte la ejecución de los indices (tracks) de los 3 discos, de este modo, existirá la posibilidad de que las bocinas que suenen vayan cambiando, de que no suene ninguna bocina, o de que suenen todas las bocinas al mismo tiempo.
La idea de que las bocinas estén pegadas a la parte inferior de la plancha de lámina es que la plancha vibre, y de este modo, que la vibración haga que las pelotas de ping pong rueden sobre ella.
La función primordial de una pelota de ping pong es la de rebotar, un movimiento discontínuo. El hecho de que un rebote grabado haga que la pelota ruede es crear una contradicción, una paradoja, o finalmente llegar a la conclusión de que los dos estados de la pelota, el discontínuo (rebote) y el contínuo (rodar), son ambos intrínsecos a la pelota e indisociables. Este fenómeno es equivalente a la teoría cuántica en la que la luz puede comportarse tanto de manera ondulatoria (continuidad) como en forma de partículas llamadas fotones (discontinuidad). Acústicamente hablando, el rebote discontínuo representa rítmo y un rebote rápido contínuo representa frecuencia. Tenemos entonces también una dialéctica o juego que se establece entre los dos elementos esenciales del sonido.
Además del diálogo que establezco entre un estado discontínuo y uno contínuo, la escultura en sí es una especie de organismo con vida o instrumento musical que recuerda procesos estocásticos que suceden en la naturaleza, como por ejemplo el rítmo de los insectos que aveces es contínuo y aveces discontínuo. Por otro lado, el movimiento físico de las pelotas sobre la mesa es una respuesta al movimiento acústico de las bocinas. De esta manera existen dos mundos en paralelo que interactúan, uno sonoro que nos lleva a lo imaginario, y uno visual que nos lleva a lo sonoro (el ruido de las pelotas rodando en la lamina).