Kienle sound radiation

from Wikipedia, the free encyclopedia

The Kienle sound radiation (also known as the Kienle sound system or Kienle resonator organ ) has been developed by Ewald Kienle since 1970 to replace the loudspeaker system used for digital sacred organs , which many church visitors find unsatisfactory.

Emission problem of digital sacred organs

Loudspeakers in churches often interfere with the overall aesthetic appearance, especially since they cannot be adequately concealed or concealed for reasons of sound. In particular, however, a loudspeaker system can not reproduce the tonal properties of a pipe organ , such as the lively, spatially staggered sound image, which is created by jumping back and forth between the organ pipes blown according to the melody, the high energy efficiency or the load-bearing capacity the sounds in the room, which is based on the resonance effect in the pipe pipe.

The omnidirectional character of the organ pipes can only be achieved to a very limited extent by using loudspeaker sound, since loudspeakers emit more and more directed radiation, particularly towards higher frequencies. In some cases, several loudspeakers are arranged next to each other in a (semicircular) circle in order to achieve a more even radiation. Another possibility is to attach a loudspeaker with the membrane pointing upwards or downwards and deflect the loudspeaker sound by means of a cone attached above or below (so-called omnidirectional radiators). Although this broadens the area of ​​uniform radiation, it cannot solve the problem of uniform all-round sound in a satisfactory manner, particularly when listeners are at different heights from the radiating device.

Functional principle of the Kienle sound radiation

Schematic representation of the excitation of a vibrating air column in an organ pipe and in the resonator of the Kienle sound radiation (black arrows: stimulating air movement; red: vibration distribution in the pipe and sound output through the openings)

The solution to the radiation problem found by Ewald Kienle is to use the resonance bodies of the organ pipes for the sound radiation, but to forego the complex air flow stimulation of the organ pipes. Instead, the air columns in the resonance bodies are excited by loudspeakers, which has been used in a similar way in loudspeaker construction since the middle of the 20th century for transmission line housings .

In the figure opposite, the sound generation processes in an organ pipe and in the resonator of the Kienle sound radiation are shown schematically. In the case of the organ pipe, the air flow required for operation (black arrows) must first be generated to a sufficient extent and supplied from below through the pipe base. The air flow is directed through the nuclear fissure towards the upper labium, where air vortices are alternately detached outwards and inwards. This process causes the air column in the pipe to vibrate. In the illustration, the vibration distribution of the fundamental tone that occurs in the pipe is shown with red curves. The oscillation node is at the level of the intersection of the curve, the antinodes are located in the area of ​​the openings through which the main part of the sound is emitted. With the pipe resonator or resonator tube of the Kienle sound radiation, the oscillation of the air column and the sound radiation take place as with the organ pipe. The air column in the tube is excited, however, by a small loudspeaker which is attached to the lower end of the resonator tube and which causes the air to move by moving its membrane back and forth.

Technical advantages of loudspeaker excitation

By eliminating the flow stimulation, the technical structure of sound radiation with organ properties is significantly simplified. In particular, all systems and devices that generate and control the air flow in a pipe organ, and thus the associated installation and maintenance work, are omitted. Sound problems that occur due to poorly controllable flow phenomena cannot arise in principle. Loudspeakers can also be controlled easily and precisely by electrical means. This makes it possible to excite not only the fundamental tone in a very targeted manner in a resonator, but also individual harmonics to the desired extent. As a result, the sounds of a very large number of organ pipes can be reproduced with a relatively small number of resonators, which leads to a significant reduction in the total number of radiating elements required without a noticeable loss of sound occurring. While several thousand, sometimes even more than 10,000, organ pipes are required for larger pipe organs, the Kienle sound radiation therefore requires significantly fewer resonators. According to the manufacturer, the currently largest Kienle sound radiation in Tbilisi consists of only around 600 resonators, but could have been implemented with half as many resonators if this had been desired for optical and / or cost reasons. When appropriately designed, the Kienle sound radiation also enables relatively easy transportability, which is advantageous, for example, when the permanent installation of systems is difficult or prohibited in a building under monument protection.

Technical execution of the Kienle sound radiation

The resonators of the Kienle sound radiation can be designed as simple tubes with a circular cross-section (without a labium) or in the form of conventional organ pipes as "pipe resonators" (with a labium, but without a core). Usually the resonators for the fundamental tones of the lower frequencies (below 64 Hz) and the resonators for the higher frequencies (above 500 Hz) are designed without a labium. Not every resonator has to be excited by its own loudspeaker. The resonators, which operate at very low frequencies and have a tube diameter of around 120 mm, are often operated with what is known as collective excitation, which excites five to ten resonators simultaneously with one or two bass loudspeakers. At high frequencies, where the tube diameter is only about 5–25 mm, several resonators can be positioned over a single loudspeaker.

In some cases, instead of the tin pipes typical for organs, resonator pipes made of zinc or aluminum are used for Kienle sound radiation, but non-metallic materials such as acrylic glass or coated or lacquered PVC are also used. In addition to optical and cost reasons, the influence of the respective material on the sound formation is also taken into account, since the sound generation is also determined by the vibrations of the pipe or pipe walls, even if only to a small extent.

The Kienle sound radiation is protected by patents from the manufacturer. The first patent (DE000002924473C2) was applied for in 1979, the currently last patent (DE102012109002B4) was granted in 2017.

Individual evidence

  1. ↑ Visualization of the air vortex in an organ pipe http://www.orgel-info.de/ in the section "Orgelforschung"
  2. ↑ Steffen Bergweiler: Body oscillation and sound radiation of acoustic waveguides taking into account wall influences and coupling effects . Chapter 8: Acoustic coupling of two neighboring organ pipes . Dissertation, University of Potsdam 2005 -> http://opus.kobv.de/ubp/volltexte/2006/656/pdf/bergweiler.pdf .