thumb|12-inch (30 cm) subwoofer [[Speaker driver|driver (loudspeaker). A driver is commonly installed in an enclosure (often a wooden cabinet) to prevent the sound waves coming off the back of the driver diaphragm from canceling out the sound waves being generated from the front of the subwoofer.]]
thumb|A typical Hi-Fi subwoofer (r.), with the subwoofer loudspeaker built into a cabinet. On the left, a version with transparent cabinet is shown where the large magnet (grayish color) of the speaker driver can be seen in the middle, close to the brown [[Electrodynamic speaker driver#Components|damper.]]
A subwoofer (or sub) is a loudspeaker designed to reproduce low-pitched audio frequencies, known as bass and sub-bass, that are lower in frequency than those which can be (optimally) generated by a woofer. The typical frequency range that is covered by a subwoofer is about for consumer products, to design additional subwoofers for his disco dance events, along with "tweeter arrays" to "boost the treble and bass at opportune moments" at his private, underground parties at The Loft. The demand for sub-bass sound reinforcement in the 1970s was driven by the important role of "powerful bass drum" in disco, as compared with rock and pop; to provide this deeper range, a third crossover point from 40 to 120 Hz (centering on 80 Hz) was added. Some car audio enthusiasts compete to produce very high sound pressure levels in the confines of their vehicle's cabin; sometimes dangerously high sound pressure levels. At first, sound pressure levels ranging from 130 decibels and 150 decibels were common during the 1980's. When the 1990's rolled around, the 170 decibel barrier was broken. Today, readings higher than 180 decibels are common in sound pressure competitions. 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.