Mechanical device used to reproduce sound waves when a power signal is applied representing those sound waves by vibrating some material that in turn creates vibrations in the air thus generating sound. peakers come in many varieties and many versions suited for a variety of tasks. The majority of speakers are dynamic designs using cones or domes vibrated by the movement of a coil of wire near a stationary magnet (the coil of wire generates a magnetic field that attracts it to and repels it from the magnet thus generating motion). Electrostatic and planar-magnetic speakers are also used along with a number of variations and other sound reproduction methods. ost speakers use a crossover to split up the audible frequency into a number of bands or sections. The frequency bands are then reproduced by different speaker drivers most capable of reproducing those sounds. Low-frequencies use woofers that are large in size. The middle frequencies are often reproduced with midrange drivers and the highs are handled by tweeters. Subwoofers are sometimes used also. Subwoofers are specially designed speakers whose purpose is to reproduce low frequency sound waves only. mall speakers are typically known as satellites or bookshelf speakers while larger speakers are known as floor-standing speakers. There are center channel speakers designed to sit on top of or below a video display to reproduce movie and television dialog and other effects. Surround channel speakers are mounted high up on the walls near or behind the listening position to create a three-dimensional, fully enveloping sound field. Most surround speakers are dipole or bipole designs. ipole speakers feature speaker drivers on two opposite sides of a speaker enclosure. Their drivers operate out of phase so that as one driver moves in the other driver on the opposite side movies out. Dipolar speakers create a broad sound on either side of the speaker and eliminate most sound from the sides of the speaker. ipolar speakers also emanate sound from two opposite sides of a speaker enclosure, but their speaker drivers operate in phase meaning that they both go in and out at the same time. Bipolar speakers create a wide soundstage with sound primarily at the front and back of the speaker but also propagating to the sides. irect radiating speakers emit sound from one side with a single set of speaker drivers. Direct radiators are easier to locate sonically. They also provide the best imaging and space delineation, but their sweet spot (optimal listening position) is fairly small and their soundstage is not as wide as that of a bipolar speaker. peaker drivers of any type are built into some form of cabinet to hold them. Most speaker enclosures are built of sturdy materials such as MDF and are braced internally with crossbeams and other such pieces to ensure they are strong and do not vibrate too much with the drivers (this is called resonance and creates a sonic distortion). The enclosures are designed in different ways to affect the sound of the drivers mounted within them, especially in regard to low frequency output. The most common types of enclosures are sealed or acoustic suspension enclosures, ported or bass reflex enclosures, bandpass enclosures, and isobaric enclosures. Of these, the most widely used are the ported and sealed designs. peakers feature some type of binding that allows power from an amplifier to be connected with speaker wire. The two primary connections are five-way binding posts and spring connections. Of the two, the five-way binding post is vastly superior. peakers all serve essentially the same function, the faithful reproduction of sound. However, there are seemingly as many variations of speaker design as there are sounds to reproduce. The important thing is finding a speaker with a good quality of sound, a good dynamic range and a reasonably flat frequency response that fills the specific needs of an individual.