The coil is oriented coaxially inside the gap, a little circular volume (a hole, slot, or groove) in the magnetic framework within which it IPOD Speaker System can turn backward and forth. The gap establishes a concentrated magnetic field between the two poles of a permanent magnet; the outside of the gap being peculiar pole and the center post (a.k.a., the pole-piece) being the other. The center post and back-plate are sometimes a lone piece called the yoke.

A mid-range speaker is a loudspeaker driver which reproduces middle frequencies. Mid-range drivers can be make-believe of assignment or composite materials, or be compression drivers. If the mid-range driver is cone-shaped, it can be mounted on the front baffle of a loudspeaker enclosure, or it can be mounted at the throat of a horn for added output exact and guidance of radiation pattern. If it is a compression driver, it is invariably mated to a horn.