Loudspeaker basics 扬声器基础.ppt

Transducers: Loudspeaker fundamentals. There are many different types of loudspeakers: Moving coil loudspeakers Electrostatic loudspeaker Ribbon loudspeaker Electro dynamic plainer loudspeaker Air transformer transducer Plasma Loudspeaker Servo loudspeaker Moving magnet loudspeakers Compression drivers Distributed mode loudspeakers This presentation will concentrate on Moving coil loudspeakers, which where invented by Kellogg over 100 years ago. Anatomy of a loudspeaker Anatomy of a loudspeaker As part of the system Discussion: Why do we design things the way we do?Design constraints: ? 2008 Harman International Industries, Incorporated. All rights reserved. Page * State of the Art: Overview Review of loudspeaker basics What is a loudspeaker Loudspeaker Anatomy Loudspeaker operation Loudspeaker deficiencies Frequency range coverage State of the Art: What is a loudspeaker? Loudspeakers are found in every day items and impact on our lives daily. They keep us informed They entertain us Allow us to stay I touch with friends and family Warn us of danger Can actually help make our surroundings more quiet Where can we find Loudspeakers? Stereos Hi Fi’s.  Televisions. Cars. Computers. Phones. Intercoms. Radios. games Toys. Alarms. State of the Art: What is a loudspeaker? A loudspeaker is a two stage transformer: Transforms Electrical energy into kinetic energy (Motion in parts of the loudspeaker) Kinetic energy reacts with the fluid medium around it to generate acoustical energy A loudspeaker is an electro magnetic transducer which transformer energy from one form to another. What is a loudspeaker? Motor system: First stage of transformer Converts the electrical input signal into a Kinetic energy Pole piece Magnet Front plate Voice coil Radiating surface: Second stage of transformer Provides a large moving surface area for the conversion of motion into sound Provides a measure of protection t