LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS

**Definition:** This place covers:

**Glossary:** - Acoustic, Sound: cover the technical field dealing with ultrasonic, sonic or infrasonic waves - Deaf aid: hearing aid - Loudspeaker: transducer mounted in a casing for producing sound - Microphone: transducer mounted in a casing for collecting sound - Stereophonic system: two- or more channel system, e.g. quadraphonic, ambisonic or similar system - Transducer: a device that converts an electrical signal to an acoustic signal with a frequency which is determined by the frequency of the electrical signal applied to the transducer, or vice versa - Microstructural device: 1. micromechanical devices comprising movable, flexible or deformable elements; 2. three-dimensional structures without movable, flexible or deformable elements, comprising microformations designed to accomplish an essential structural function for interacting with their environment, as opposed to purely electronic or chemical functions, regardless of whether the structures are combined with microelectronic devices or formed from specific materials; - Microstructural system: 1. systems of cooperating microstructural devices; 2. microelectro-mechanical or microopto-mechanical systems, which combine on a common substrate the specific features of microstructural devices and electrical or optical components, e.g. for controlling, analysing or signalling the functioning of microstructural devices.