Sea and Sun croatian choral

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Nikola Bašić, architect of the Zadar Sea Organ
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The paper deals with the acoustical and musical solution to the newly built urban musical attraction in Zadar, Croatia, named "Morske orgulje" ("Sea Organ"). The said installation is implanted into the stony stairy promenade alongside the seashore. The 35 organ pipes are built subterraneanly, into tunnels attached to the flank of a central service channel. Each organ pipe is blown by a column of air, pushed in turn by a column of wave-moved water, through a plastic tube immersed into the water. The pipes' sound emanates to the surroundings through appertures in the vertical planes of the uppermost stairs. The 7 successive groups of pipes are alternately tuned to two musically cognate chords of the diatonic major scale. The outcome of played tones and/or chords is a function of random time- and space distribution of the wave energy to particular organ pipes. In addition to the customary presentation of technical drawings and photos, an audio recording of organ sounds caught at the location in various weather conditions will be reproduced during the paper session. Following the recent "live" experience on site, the overall acoustical and musical result will be discussed in detail.

The installation of the Sea Organ has been completed end - March, 2005, a fortnight before the opening ceremony. Since then, the pipes have been active all the time, night and day. The lot of people reportedly visits the new city attraction, mostly with enthusiasm. The internet polling among Zadar citizens (as on May 6th, 2005) resulted thus: affirmative 77.9%; indifferent 9.3%; negative 12.7%.
Until now, the members of the task team had occasionally monitored the Sea Organ behavior. The following can be established:
" The overall sounding generally matches the original design idea and expectations.
" No more than 5 to 6 pipes can be heard at a time on a standpoint.
" In some extreme weather situations the loudness was exaggerated.
" Some of the flue pipes occasionally overblow.

The task team firmly recomended to the Zadar authorities to organize a monitoring of the Sea Organ operation during next 6 months (at least) in order to encompass the vast majority of various weather features. A resident person, preferably an experienced musician, should be instructed to monitor and record the peculiarities of the sound and to measure sound pressure level in dBA on the spot. Following this period, the task team will recommend the necessary measures to optimize the Sea Organ operation in all aspects.
The author wishes to thank Messrs. Nikola Bašić, Tomislav Faullend Heferer and Ante Petrina for their dedicated cooperation in preparing this report and for the supply of the technical documentation items from their expert field.

Tube-pipe tandem, architect's sketch.

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