Breathing ball

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A Breathing ball is in the acoustic model idea of an ideal speaker that the sound isotropic , distributed so evenly in all directions. In mathematical terms, it is a monopole radiator that emits a point-symmetrical spherical wave . The radius of the breathing sphere oscillates with a small amplitude around the rest value .

For acoustic measurement technology , it would be desirable to have a sound transmitter that radiates uniformly on all sides; however, its implementation in the form of a shot peening encounters difficulties. After all, its behavior can be  approximated within certain limits by a regular dodecahedron  (twelve-sided) or icosahedron (twenty-sided), in the middle of which loudspeakers of the same type and supplied with the same electrical signals are used.

The name monopole for the zero-order spherical emitter comes from considering the multipole development ( spherical surface function ) of the sound field . However, radiation characteristics of the higher multipoles ( dipole or spherical radiator 1st order, quadrupole or spherical radiator 2nd order ...) are more common.

literature

  • Siegfried Wirsum: Practical sound reinforcement technology. Device concepts, installation, optimization. Franzis-Verlag GmbH, Munich 1991, ISBN 3-7723-5862-4 .
  • Vance Dickason: Loudspeaker construction. 4th edition, Elektor-Verlag, Aachen, 2007, ISBN 978-3-89576-116-4