Before revision: The older and larger, lower-frequency multibeam sonar systems, that required considerable time and effort mounting them onto a ship's hull, employed conventional tonpliz-type transducer elements, which provided a usable bandwidth of approximately 1/3 octave.
After revision: The older and larger, lower-frequency multibeam sonar systems, that required considerable time and effort mounting them onto a ship's hull, used conventional tonpilz-type transducer elements, which provided a usable bandwidth of approximately 1/3 octave.