Dr. Blue at the Underwater Sound Reference Division

Abstract

At the Underwater Sound Reference Division Dr. Blue had many varied interests including acoustic metrology, acoustic materials research, enginering acoustics, underwater transducers, and bioacoustics. He performed the first thorough study on the reproducibility of calibrations of standard hydrophones. He supported the development of traveling-wave tubes and large pressure vessels for calibrating Navy sonar transducers and for the measurement of acoustic materials. The Acoustic Pressue Tank Facility is a 30<th>000-gal acoustic test vessel ideally suited for acoustic measurements at hydrostatic pressures up to 2700 psi and at frequencies as low as 1.0 kHz and can accommodate acoustic devices up to 6 ft in diameter. Dr. Blue supported research for improved measurement techniques for determining the properties of acoustic materials. Dr. Blue actively supported the development of new elastomeric materials used in the construction of underwater transducers. The Sonar Transducer Reliability Improvement Program was an extinsive program to properly specify a sonar transducer for Navy applications. He first suggested that coupler reciprocity might be used to perform ultra-precise calibrations of hydrophones. He also supported research in manatee vocalizations and dolphin echolocation clicks. Low-noise hydrophones with noise levels better than sea-state zero were developed for general use.