What is the difference between dipole and bipolar loudspeakers?
A dipole loudspeaker, e.g. an open baffle, emits the acoustic energy to front and back 180° out of phase, i.e. it simultaneously generates pressure to the front and a partial vacuum to the rear – or vice versa. The pressure compensation in the proximity of the membrane (acoustic short-circuit) means that a great part of the bass energy is lost. Bipolar speakers on the other hand emit the sound to front and back in phase. These have an extra chassis on the rear wall of the cabinet. This method generates a spacious sound field while managing to avoid an acoustic short-circuit.
