From Transducers and Arrays for Underwater Sound


The development of underwater electroacoustic transducers expanded rapidly during the twentieth century, and continues to be a growing field of knowledge, with many significant applications, one that combines mechanics, electricity, magnetism, solid state physics and acoustics. In the most general sense, a transducer is a process or a device that converts energy from one form to another. Thus an electroacoustic transducer converts electrical energy to acoustical energy or vice versa. Such processes and devices are very common. For example, a thunderstorm is a naturally occurring process in which electrical energy, made visible by the lightning flash, is partially converted to the sound of thunder. On the other hand, the moving coil loudspeaker used in radio, television and other sound systems is a familiar man-made transducer. Loudspeakers are so common that they probably outnumber people in developed parts of the world. The familiar designations loudspeaker and microphone for transducers used as sources and receivers of sound in air become projector and hydrophone for sources and receivers in water. The term SONAR ( SOund Navigation And Ranging) is used for the process of detecting and locating objects by receiving the sounds they emit (passive sonar), or by receiving the echoes reflected from them when they are insonified (see Glossary of Terms) in echo-ranging (active sonar). Every use of sound in the water requires transducers for the generation and reception of the sound, and most of the transducers are based on electroacoustics. Several non-electroacoustic...

Products & Services
Pulser-receivers generate ultrasonic pulses, which are propagated into materials for NDT testing.
Speed Logs
Speed logs measure the transit speed of vessels.
Underwater Acoustic Transducers
Underwater acoustic transducers contain both transmitters and receivers and use distance and directional data for communication, mapping and navigation.
Ultrasonic Transducers
Ultrasonic transducers send and receive waves for many types of sensing. Examples include distance, proximity, level, nondestructive evaluation, web break detection, counting, and security applications.
Soundproofing and Acoustic Materials
Soundproofing and acoustic materials are used to attenuate, deaden, or control sound and noise levels from machinery and other sources for environmental amelioration and regulatory compliance. 

Topics of Interest

Overview This chapter will describe the six major electroacoustic transduction mechanisms in a unified way using one-dimensional models to derive pairs of linear equations specific to each mechanism...

Overview The previous six chapters presented the status of underwater sound transducers and arrays at the beginning of the twenty first century in considerable detail, but with a minimum of...

Overview Active sonar and acoustic communication systems rely on electroacoustic transducers which "project" sound that is subsequently detected by hydrophones through a direct path or reflection...

J. Fleming Dias Agilent Technologies Palo Alto, California 5.1 Introduction In general terms, the transduction process involves the transformation of one form of energy into another form. This...

by Ray Rayburn 38.1 The Design of Sound Systems Sound systems are made of three primary components: Input transducers Signal processing Output transducers 38.1.1 Analog Systems Transducers are...