Editing Subwoofer (section)

===Car audio===
[[File:Multiple subwoofers in a car hatchback.jpg|thumb|Multiple subwoofers in a hatchback car]]

Automobiles are not well suited for the "hidden" subwoofer approach due to space limitations in the passenger compartments. It is not possible, in most circumstances, to fit such large drivers and enclosures into doors or dashboards, so subwoofers are installed in the trunk or back seat space. Some [[car audio]] enthusiasts compete to produce very high [[Sound#Sound Pressure Level|sound pressure]] levels in the confines of their vehicle's cabin; sometimes dangerously high sound pressure levels. The "SPL wars" have drawn much attention to subwoofers in general, but subjective competitions in sound quality ("SQ") have not gained equivalent popularity. Top SPL cars are not able to play normal music, or perhaps even to drive normally as they are designed solely for competition. Many non-competition subwoofers are also capable of generating high levels in cars due to the small volume of a typical car interior. High sound levels can cause hearing loss and [[tinnitus]] if one is exposed to them for an extended period of time.<ref name=Passchier2000 />

In the 2000s, several car audio manufacturers produced subwoofers using non-circular shapes, including Boston Acoustic, Kicker, Sony, Bazooka, and X-Tant. Other major car audio manufacturers like Rockford Fosgate did not follow suit since non-circular subwoofer shapes typically carry some sort of distortion penalties.<ref name=AutoOnA /><ref name=12vhndbk /> In situations of limited mounting space they provide a greater cone area and assuming all other variables are constant, greater maximum output. An important factor in the "square sub vs round sub" argument is the effects of the enclosure used. In a sealed enclosure, the maximum displacement is determined by

<math>V_\mathrm{d} = x_\mathrm{max} \times S_\mathrm{d}</math>

where
* <math>V_\mathrm{d}</math> is the volume of displacement (in m<sup>3</sup>)
* <math>x_\mathrm{max}</math> is the amount of linear excursion the speaker is mechanically capable of (in m)
* <math>S_\mathrm{d}</math> is the cone area of the subwoofer (in m<sup>2</sup>).
These are some of the [[Thiele/Small]] parameters which can either be measured or found with the driver specifications.