Operation
In operation, a signal is delivered to the voice coil by means of electrical wires, from the amplifier through speaker cable, then through flexible tinsel wire to the moving coil. The current creates a magnetic field that causes the diaphragm to be alternately attracted to, and repelled by, the fixed magnet as the electrical signal varies. The resulting back-and-forth motion drives the air in front of the diaphragm, resulting in pressure differentials that travel away as sound waves.
The spider and surround act as a tensioned spring centering mechanism, to both concentrically center the voice coil within the magnet assembly, and to center the front-to-back voice coil position within the magnet assembly when power is removed.
The voice coil and magnet essentially form a linear motor working against the centering spring tension of the spider and surround. If there were no restriction on travel distance imposed by the spider and surround, the voice coil could be ejected from the magnet assembly at high power levels, or travel inward deep enough to collide with the back of the magnet assembly. The majority of speaker drivers only work against the centering tension of the spider and surround, and do not actively monitor the position of the driver element or attempt to precisely position it, as occurs in servomechanisms.
Read more about this topic: Speaker Driver
Famous quotes containing the word operation:
“Waiting for the race to become official, he began to feel as if he had as much effect on the final outcome of the operation as a single piece of a jumbo jigsaw puzzle has to its predetermined final design. Only the addition of the missing fragments of the puzzle would reveal if the picture was as he guessed it would be.”
—Stanley Kubrick (b. 1928)
“It is critical vision alone which can mitigate the unimpeded operation of the automatic.”
—Marshall McLuhan (1911–1980)
“You may read any quantity of books, and you may almost as ignorant as you were at starting, if you don’t have, at the back of your minds, the change for words in definite images which can only be acquired through the operation of your observing faculties on the phenomena of nature.”
—Thomas Henry Huxley (1825–95)