Passive radiator : How it works ?

The passive radiator must be integrated in a box with an active loudspeaker. This passive radiator, although at first it may look like a "classic" loudspeaker, does not in fact have any engine part. Thus, one will not find in its design of coil, magnet and power supply. Similarly, it will not be electrically connected to a power amplifier.

To diffuse sound, the passive radiator will use the air pressures and depressions induced by the active loudspeaker in the body to vibrate its membrane and produce sound, thus providing deep bass. Its resonance frequency is determined by its mass and the air contained in the enclosure. The resonance frequency can therefore be varied on many models and tuned to the speaker by adding mass.