Editing Acoustics (section)

=== Transduction in acoustics ===
[[Image:3.5 Inch Speaker.jpg|thumb|An inexpensive low fidelity 3.5&nbsp;inch '''driver''', typically found in small radios]]
A [[transducer]] is a device for converting one form of energy into another.  In an electroacoustic context, this means converting sound energy into electrical energy (or vice versa). Electroacoustic transducers include [[loudspeaker]]s, [[microphone]]s, [[particle velocity]] sensors, [[hydrophone]]s and [[sonar]] projectors. These devices convert a sound wave to or from an electric signal. The most widely used transduction principles are [[electromagnetism]], [[electrostatics]] and [[piezoelectricity]].

The transducers in most common loudspeakers (e.g. [[woofer]]s and [[tweeter]]s), are electromagnetic  devices that generate waves using a suspended diaphragm driven by an electromagnetic [[voice coil]], sending off pressure waves. [[Electret microphone]]s and [[condenser microphone]]s employ electrostatics—as the sound wave strikes the microphone's diaphragm, it moves and induces a voltage change. The ultrasonic systems used in medical ultrasonography employ piezoelectric transducers. These are made from special ceramics in which mechanical vibrations and electrical fields are interlinked through a property of the material itself.