page_title: WOOx Technology
section_title: The wOOx Bass Radiator
hierarchical_section_title: WOOx Technology / The wOOx Bass Radiator
caption_attribution_description: English: A passive radiator with wOOx Technology, on top of a loudspeaker system from a Philips FW-C80 mini hi-fi system. Deutsch: Ein passiver Strahler mit wOOx Technologie, oben auf einer Lautsprecherbox von einer Philips FW-C80 kompakt Stereoanlage.
context_page_description: wOOx technology is a brand created by Philips to identify loudspeaker systems that employ passive radiator technology in conjunction with active equalization to maximize the output of the passive diaphragm. wOOx Technology optimizes the active bass driver, the passive bass radiator, and the active equalization curve to obtain maximum low-frequency reproduction in a relatively compact configuration.
context_section_description: The primary element of a wOOx Technology speaker system is the bass radiator. The wOOx bass radiator (referred to in marketing literature as the wOOx-Slave) is functionally indistinguishable from typical "passive radiator" diaphragms previously employed in loudspeaker systems. Early wOOx radiators used a patented design with two foam-rubber suspension rings instead of the typical single ring, and a symmetrical sandwich construction.
  Typical passive radiator theory dictates that the passive radiator should be capable of displacing at least twice the volume of air that the active driver displaces through its own stroke. To satisfy this requirement, passive radiators traditionally have a larger surface area than the active driver. The dual-suspension design of the wOOx bass radiator allows the radiator to undergo extreme excursions, so the wOOx radiator displaces the necessary air volume without being larger than the active driver, enabling easier integration into consumer electronics products. More recent embodiments of the wOOx bass radiator use a single-roll suspension.
  The wOOx radiator incorporates a mass element in the center of its diaphragm, which is used to adjust the tuning frequency of the loudspeaker enclosure. In this sense, a loudspeaker enclosure with passive radiators emulates a mass-spring system, much like the helmholtz resonator devices (bass reflex ports) more commonly used to tune loudspeaker enclosures. However, the amount of mass suspended on a passive radiator diaphragm enables extremely deep tuning frequencies to be possible in small enclosures. However, like any passive radiator system, it is possible to damage the bass radiator by driving it beyond its mechanical limits. To avoid this, some wOOx systems use an additional reflex vent, having the same tuning as the wOOx radiator. This relieves excess pressure that could tear the bass radiator apart.
caption: Passive radiator with wOOx Technology
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