Ann KapustaJune 1, 2007Math 5Professor BarnettThe Sea Organ: A Musical Connection between Land andSeaI. IntroductionFound in the Zadar harbor on the island of Croatia, the Sea Organ is a unique instrument that produces an incredible array of sounds. While using the basic mechanics of ancient instruments, the Sea Organ is rare in its construction and its melodic sounds. Through this paper the history of instruments that have influenced the creation of the Sea Organ, as well as the actual physical construction of it will be discussed. Finally a simplified acoustical analysis of the Sea Organ will be done using the knowledge gained throughout this class.II. HistoryThe origination of the sea organ’s acoustical construction dates back to the 3rd century BC. The hydraulis, the first documented instrument that used water and air pressure to create music, was invented by Ctesibius of Alexandria. With well documented use up until the 5th century AD, this instrument was the predecessor of thewell known pipe organ that is used today. The instrument used a series of vertical pipes that were held above and connected to an air chamber. The pressure in the air chamber was supplied by a water pump system that kept the air pressure underneath the pipesconstant. This allowed the pipes to remain in tune and sound evenly despite little changes in air pressure due to weather fluctuations. Air pressure can change up to 5-10% depending on the weather and these fluctuations (while not aurally perceptible) undoubtedly affected the pressurized air in the pipes. The instrument was played by depressing keys or using slides to let the pressurized air into the pipes. The hydraulis is also commonly referred to as the “water organ”. (“hydraulis”, np; Water Organ, np)After the 5th century AD, the hydraulis was rapidly being replaced by more sophisticated methods of air pressure-pipe instruments. By the 9th century AD, the hydraulis was effectively extinct from the musical repertoire; the more common version of the pipe organ was now being used. (Water Organ, np) The next instance where we see a new version of the water-pipe instrument construction comes in the 1980’s when the Exploratorium in San Francisco, California constructed an instrument to be played by theSan Francisco Bay. The Wave Organ, constructed in 1986, uses thehydraulis’ basic idea that water pressure can be used to constrain air pressure that then excites a pipe system. The wave organ was designed and developed by Peter Richards. The idea arose when he listened to recordings of a vent pipe on a dock in Sydney, Australia that was excited by the crashing waves. (the wave organ,np)The actual construction for the Wave Organ in San Francisco is a different take on the original concept of the ancient hydraulis. The Wave Organ actually uses the chaotic flow of the water as well as the rise and fall of the tides to excite the pipes as opposed to using air pressure created by the moving water. The construction of the wave organ uses a series of 25 assorted PVC pipes that are held in place with concrete. The tops of the pipes are built into theamphitheater-type structure and are the producers of the sounds ofthe Wave Organ. In order to hear the sounds, one must sit next to the top of one of these protruding pipes. The sculpture itself is made from an assortment of granite, marble, and concrete pieces. The sounds created by the wave organ come from the waves crashing into the closed-open pipe constructions underneath the seating area, as well as the water flowing in and out of the pipes. The rise and fall of the tides also affects the sounds produced by the Wave Organ. (the wave organ, np)While the Wave Organ was an original take on the idea to use water to excite pipe modes, the sounds produced by the pipes in San Francisco is something less than melodic. The wave organ is more a piece of art than a musical instrument. The sounds produced by the wave organ are described as listening to the “world’s largest sea shell”, with a selection of grumbles, low crashing of waves, and hums. (Edwards, np)The Sea Organ is a combination of both the creation of sounds and melodies that was originally used in the construction ofthe hydraulis as well as the aesthetic and seaside design of the Wave Organ. The Sea Organ is located in the Zadar harbor in Croatia. The Sea Organ was designed by Nikola Basic in order to restore part of the sea coast of Croatia after it had been all but destroyed during World War II and was officially opened in April of 2005. It was designed to restore the Zadar harbor back to a place of beauty and a place where the there exists a true connection between the sea and the land. (The Sea Organ, np)III. ConstructionThe Sea Organ’s construction is very simple, yet very effective. It is an alteration on the previously discussed hydraulis where water is used to change air pressure which in turn excites differentpipes of a multi-pipe system. The Sea Organ is 70 meters long and divided into seven separate stair like sections. There are 35 plastic“organ” pipes built underneath the white marble staircase structure, separated into five pipes in each of the seven sections.Each of the seven sections has a different number of actual stairs, with one open end of every pipe built into the top stair. The number of stairs decreases by one in each segment allowing for thepipes to be of different lengths to produce different acoustical sounds. The maximum number of stairs is eight and the minimum is two. The segments with the greater number of stairs produce the lowest frequencies heard by visitors to the Sea Organ, and the segments with lower number of stairs produce higher pitches. The pipes themselves are placed 1.5 meters apart in each segment. (The Sea Organ, np)The pipes are a slightly more difficult construction in order toaccount for both the water and the air pressure that changes as thewaves crash into the structure. The pipe is essentially an open-open pipe with one end open to the water, and the other end opening up into an air chamber that resonates the sound before releasing it out through holes in the stairs.The one open end of the pipe is immersed under the average sea level so that regardless of the tides it is always under water. As thewaves crash into the stairs, the water is pushed up into the pipe (the water pressure is increased). The pipe narrows as it is elevated so that