What do dipole speakers do ?

Question

what do dipole speakers do ,can any tell me ,why do it need two sides ,and what do the two sides do. can someone someone please explain

Answer 1

Dipole speakers have drivers on both sides. One side is wired backwards, a.k.a., out of phase from the other. The idea behind this is to make sounds less "locatable" when they are being used for surround duty. In realty, I can't really tell the difference between these and other designs.

Answer 2

A dipole speaker works by creating air movement (as sound pressure waves) directly from the front and back surfaces of the driver, rather than by impedance matching one or both outputs to the air. As a result, diaphragm motion is constrained primarily by the driver's restoring force (eg, diaphragm suspension) and not by acoustic loading from an enclosure. This implies that cone motion will be larger at the same output level than in a more usual enclosure, and that power handling will be accordingly limited. Especially at lower frequencies, dipole drivers tend to be large and flat, and necessarily open at both front and back. For example, electrostatic or ribbon drivers, though a conventional cone driver mounted in an open baffle also works as a dipole loudspeaker. All of these variations are characterized by a "figure-of-eight" radiation pattern in which the loudness falls toward the sides of the enclosure where interference between front and back waves are maximized. Sometimes the enclosure is modified into an "H-frame" with the driver located on a wall dividing two open compartments. Such enclosures require some control over the radiated sound from the rear of the enclosure to achieve the desired response. This is usually done by mounting two drivers one over the other in a push-pull configuration.

An advantage of dipoles is that the sound is concentrated in the listening area due to the figure-of-eight polar response. This means that for a given output loudness, locations falling within the "dead-zone" of the speaker do not perceive as loud a sound as they would with more traditional enclosures. However, these enclosures are less efficient because, for the same driver a dipole results in less sound pressure level than a closed or ported enclosure, and certainly far less than a properly designed horn. This means that the drivers mounted on a dipole enclosure must have large maximum excursions or large square areas or both.