An Air Sound Transducer for Frequencies in the Range 50 kHz to 100 kHz Using the Sell Principle

ISSN： 1610-1928

Source： Acta Acustica united with Acustica, Vol.30, Iss.1, 1974-01, pp. : 30-39

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Abstract

Investigations have been carried out on Sell transducers having grooved counter electrodes as regards the transmission curves, directional pattern and time stability of the transducer characteristics. Below the first resonance frequency the transmission for the transmitter varied as square of the frequency (f) and the response of the receiver was frequency independent. The time stability was satisfactory using suitable electrodes and lay out of the counter electrodes. The directional pattern showed pronounced secondary lobes as for rigid discs (measurement in the direction of the first secondary lobe: ≍ −17.5 dB). By means of an absorbent conduit above the Sell transducer the measured value in the direction of the first secondary lobe could be reduced to about −40 dB (f = 70kHz).