Tonpilz
Encyclopedia
The term tonpilz or "acoustic mushroom" may refer to a certain type of underwater electro-acoustic transducer. By sandwiching active (i.e. piezoelectric
or magnetostrictive
) materials between a light, stiff radiating head mass and a heavy tail mass, the transducer can effectively operate as either a projector (source) or a hydrophone
(underwater acoustic receiver). The transducer's size, odd shape, and acoustic projection capabilities have earned it the moniker "tonpilz".
Typically, tonpilz transducers are used in sonar
applications. To maximize efficiency transducers are often placed in arrays: a grid of sometimes hundreds of transducers. This arrangement also allows for beamforming
and steering.
Transducers of this form also lend themselves to compensation against the hydrostatic pressures encountered in sonar, particularly for submarine applications.
"Acoustic mushroom" may also refer to a passive ceiling or wall treatment applied to the insides of concert auditoria, including the Royal Albert Hall
.
Piezoelectricity
Piezoelectricity is the charge which accumulates in certain solid materials in response to applied mechanical stress. The word piezoelectricity means electricity resulting from pressure...
or magnetostrictive
Magnetostriction
Magnetostriction is a property of ferromagnetic materials that causes them to change their shape or dimensions during the process of magnetization. The variation of material's magnetization due to the applied magnetic field changes the magnetostrictive strain until reaching its saturation value, λ...
) materials between a light, stiff radiating head mass and a heavy tail mass, the transducer can effectively operate as either a projector (source) or a hydrophone
Hydrophone
A hydrophone is a microphone designed to be used underwater for recording or listening to underwater sound. Most hydrophones are based on a piezoelectric transducer that generates electricity when subjected to a pressure change...
(underwater acoustic receiver). The transducer's size, odd shape, and acoustic projection capabilities have earned it the moniker "tonpilz".
Typically, tonpilz transducers are used in sonar
Sonar
Sonar is a technique that uses sound propagation to navigate, communicate with or detect other vessels...
applications. To maximize efficiency transducers are often placed in arrays: a grid of sometimes hundreds of transducers. This arrangement also allows for beamforming
Beamforming
Beamforming is a signal processing technique used in sensor arrays for directional signal transmission or reception. This is achieved by combining elements in the array in a way where signals at particular angles experience constructive interference and while others experience destructive...
and steering.
Transducers of this form also lend themselves to compensation against the hydrostatic pressures encountered in sonar, particularly for submarine applications.
"Acoustic mushroom" may also refer to a passive ceiling or wall treatment applied to the insides of concert auditoria, including the Royal Albert Hall
Royal Albert Hall
The Royal Albert Hall is a concert hall situated on the northern edge of the South Kensington area, in the City of Westminster, London, England, best known for holding the annual summer Proms concerts since 1941....
.