Zur Frage der Meßgenauigkeit bei hydrobioakustischen Untersuchungen in Aquarien und Flachwassergebieten
Freytag, G. (1967). Zur Frage der Meßgenauigkeit bei hydrobioakustischen Untersuchungen in Aquarien und Flachwassergebieten. Helgol. Wiss. Meeresunters. 15(1-4): 376-389. https://dx.doi.org/10.1007/BF01618635
In: Helgoländer Wissenschaftliche Meeresuntersuchungen. Biologische Anstalt Helgoland: Hamburg. ISSN 0017-9957, more
Also appears in:Kinne, O.; Aurich, H. (Ed.) (1967). Vorträge und Diskussionen. Erstes Europäisches Symposion über Meeresbiologie = Papers and discussions. First European Symposium on Marine Biology = Rapports et discussions. Premier symposium européen sur biologie marine. Helgoländer Wissenschaftliche Meeresuntersuchungen, 15(1-4). Biologische Anstalt Helgoland: Hamburg. 669 pp., more
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| Abstract |
The accuracy of bioacoustic measurements lies, according to data from literature, within ± 0.01 dB referred to 1 µb or p0. Such high degree of accuracy is justified neither by test accuracies of noise measuring equipment nor by the properties of a sound field limited by soft boundaries. According to our measurements in aquaria of various sizes and different boundaries and the results on frequency dependent damping in columns of liquid with zero impedance byKuhl &Tamm (1953), it can be demonstrated that the sound propagation in an aquarium is considerably reduced below the lowest cut-off-frequency and that the damping of sound waves can reach 20 dB or more due to the soft sound field boundaries. It is pointed out that no type of aquarium is suitable for measurements of sound pressure and relative amplitudes of a given spectrum in the frequency range of bioacoustical interest. From the standpoint of physical measuring techniques all bioacoustical data measured in aquaria are incorrect. |
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