Solar Organetti

 

Please reference this paper for a full description of the project. There is also this video, and a lower resolution video.

Introduction

In this project, the desire was to create modular, organic sound objects powered by the sun. The objects would breathe with the brightness of the sun, and have a subtle and complex envelope: some sort of ground to some beautifully tuned wind chimes heard in a garden. They would from trees and light posts, like fruit or icicles. The interactive portion of the organetti is compositional: they set in motion by design choices, yet subject to chance (weather).

Background

There were some interesting historical precedents for such a project. Along with the Utrecht Psalter, the Stuttgart Psalter from c. 820-830 illustrates various organs and other instruments. Likely made in a northern French scriptorium, the manuscript illustrates Psalm 136/137 ("By the rivers of Babylon...") with little organs hanging from trees; this image is found in early Greek Psalters as well. These organetti, possibly a fantasy, a miniature of reality, and/or an artistic convention, differ from the solar ones in that they have seven pipes each, six or seven little key-tabs below the pipes, a frame, and an oblique bar across the pipe rows. Later representations become less reliable until perhaps the later thirteenth century [4]. There may be some connection with the panpipes sometimes shown hanging in foliage in pagan Roman sculpture (see figure 1).

Another account of interest hails from the Lakota Sioux. The Lakotan Siouan Sundancers blow a bird bone whistle that serves as a conduit between the source of power and humanity, that is, Wakan-Tanka and the Sundancers. During the Sundance, power is said to flow from Wakan-Tanka through the sun and the sacred central tree in the dance ground, to the Sundancer, who blows a hollow bird bone whistle, which fills with that power [1].


In Greek legend, the nymph Syrinx was pursued by Pan and turned into a hollow reed, the hollow stem being a lilac from which he made his first pipe. This relates to many images of vegetation sprouting as visual sound (see figure 2).

The term organetto in Italian refers to a bird, as well as a type of pasta; in this case, we refer to a small portative organ, with one hand playing the pitches, and the other pumping the bellows (figure 3).

The solar organetto has some of the same characteristics as the traditional one: it’s portable, uses pipes, and has its own source of wind power. It would be up to the artist to decide the number of solar organetti and their position. There are also organetti morti, which are non-functional pipes introduced into the façade of a pipe organ to achieve visual symmetry.

For information on the solar engine, the details are provided in this paper.

Implementation


There are many general questions to address—To what extent do instruments/musical objects determine a composition? To what extent is the composition the musical object, and how much of a composition is the instrument on which it is executed? Of what does a performance consist, and what is the role of the performer versus the composer versus the instrument builder? For instance, the way John Cage’s Organ2/ASLSP has been interpreted [15], or to use Cage again, the use of star maps and aleatoric techniques in his difficult Etudes [16].


In the case of the organetti, there are many degrees of freedom for the composer. For example, there is a degree of indeterminacy via the weather, a degree of determinacy via the patterns the sun traces across the Earth (the current organetto uses passive solar panels), and another degree of determinacy built into the solar engine. In full sun, it begins playing in the morning, with increasingly short periods of charging, and only slightly longer periods of operation, until the sun reaches its zenith. The entire pipe vibrates at its fundamental after the attack (that consists of partials of the pipe). The attack is when the most charge flows from the capacitors into the motor; as the capacitors discharge, other partials of the pipe are elicited.

The path of the sun in the sky is determined by where on Earth the organetto is. Lower latitudes get more sun, and therefore more current, however higher latitudes have longer days some parts of the year. There are excellent models for computing the sun’s position and solar intensity at various stations around the world [14]. Neglecting weather, global dimming, and other chance factors, these data could be used to get more precise performances from the system; the performance would change daily, albeit subtly, producing complex variation over timescales that are longer than a typical composition (months rather than minutes). There are weather patterns that occur over long enough periods that one could surmise that, for example, it will run less often in Seattle than in Florida. Depending on the panels’ location, the sprouting of leaves on trees, shadows from new buildings, and other exogenous occurrences would change the system’s behavior.

In this organetto, at this time of year (30 January 2007), and at this latitude (New York City is 4043’ N), from sunrise the system charged until there was a first cycle, which was 8 seconds on and then a span of minutes off. Sunrise was at 7:07AM (112 E-SE), noon was 12:09 PM (sun at 32 above horizon), and sunset was at 5:12PM (248 W-SW). The off period shortened as the sun rose in the sky. When the sun neared its zenith, the off interval was only 15 seconds. The off periods grew longer at sunset’s approach, until there was no more sun and the system waited for the next sunrise.


The solar engine itself may be adjusted; one may choose a solar array and capacitor bundle that, on a sunny day, produces much longer on periods, but also much longer charging periods. In such an organetto, a cloudy day might produce one ff sigh, or nothing at all.

 

Conclusions

There are many other types of wind-blown sound elements that could be used, for example, ocarinas, made of clay, conch shells, and glass (embedded with a solar-collecting layer). One could also use the engine to create percussive instruments and plucked-string instruments. With more sound sources, there are more possibilities.


The video [18] shows an organetto in an incredibly noisy urban environment; there are no fewer than a dozen luxury condominium developments being built within five blocks of each other. It is interesting to note the similarity between the sound of the plane overhead and the sound of the organetto.
Development of the system with larger capacitor arrays would give flexibility in the selection of blowers, loudness, time values, and sound elements. The design allows for customized responses to varying solar conditions around the globe; this could really be described as a virtuoso element, since the panels’ alignment could get very detailed. In matching pipes to wind sources there is much to be discovered. For instance, in stopped pipes, which have short attacks and accommodating pressure/fundamental pitch regimes, there is no first harmonic when the pipe is overblown; or, if one were skilled, one could voice the pipes specifically (the stopped pipe used in the video shows “nicking” at the languid that induces turbulence to the airflow) [18].


It is hoped that the organetti’s open-ended quality will extend into unforeseen areas, as imaginative as the people who illuminated those beautiful scrolls so many centuries ago.

See paper for references and footnotes.

 

Figure 1. Sacrifice to Hercules. Note pan pipes in arbor. [2]

Figure 2. Pan. Note foliage from syrinx. [5]
Figure 3. Musician with portative. [6]
Figure 6. Morning Sun, Brooklyn
Figure 7. Collecting energy through window, afternoon.