What Is a Loudspeaker Passive Radiator?

A loudspeaker passive radiator increases the ability to fine-tune loudspeaker sound quality.

A loudspeaker refers to speakers that convert electrical signals into sounds. A loudspeaker passive radiator reduces the enclosure size of the loudspeaker.

Loudspeaker Enclosures

A loudspeaker enclosure refers to a dedicated cabinet designed to mount speaker drivers and other loudspeaker hardware such as amplifiers. Loudspeaker enclosures help prevent sound waves which are produced by the driver's diaphragm as it combines with the front of the driver. These sounds are out of phase with each other and can result in sound distortion.

Speaker Drivers

A speaker driver acts as a transducer device. A transducer converts one source of energy, such as electrical signals, into sound waves. Speaker drivers use a diaphragm. a cone-shaped membrane that attaches to a coil and moves back and forth to produce pressure waves. The loudspeaker enclosure isolates the acoustic waves generated from the rear of the cone.

Passive Radiator

A loudspeaker passive radiator contains both the active driver and an extra "passive" cone. The passive cone contains no coil and does not attach to a circuit. Air pressure generated by the active cone moves the passive one, adjusting the mass of the speaker and enabling the user to finely adjust speaker frequency within the enclosure.

References

• Human Speakers: Passive Radiators
• "Loudspeaker Design Cookbook"; Vance Dickason; 2005

Resources

• "Loudspeaker Handbook"; John Eargle; 2003