Thermophone
Thermophone
Speaker that uses heat to make sound
A thermophone is a type of transducer that converts an electrical singal into heat, which then becomes sound. It can be thought of as a type of loudspeaker that uses heat fluctuations to produce sound, instead of mecahnical vibration.
The basic principle of the thermophone has been known since the 19th century.[1] Thermophones have been used to calibrate acoustical apparatus (like microphones) since the 20th century.[2] In recent years, the name thermoacoustic speaker has also been used.[3]