3. JBL ES150PBK 300-Watt Powered 10-Inch Subwoofer

Big bass performance of a full-size subwoofer, but in a compact design

Dual BP1204 12-Inch 1100-Watt Illumination Bandpass Subwoofer

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  • Review
  • TAG : Shallow Subwoofer Rear View
  • Tom Horral, a Boston-based acoustician, blames complaints about modern movies being too loud on subwoofers. He says that before subwoofers made it possible to have loud, relatively undistorted bass, movie sound levels were limited by the distortion in less capable systems at low frequency and high levels.

    After the introduction of Sensurround, owners began installing permanent subwoofer systems. was a six channel film sound format introduced in 1976 that used two subwoofer channels for stereo reproduction of low frequencies. In 1981, introduced a dedicated cinema subwoofer model tuned to around 20 Hz: the 8182. Starting in 1983, certification of the cinema sound experience quantified the parameters of good audio for watching films, including requirements for subwoofer performance levels and enough isolation from outside sounds so that noise did not interfere with the listening experience. This helped provide guidelines for multiplex cinema owners who wanted to isolate each individual cinema from its neighbors, even as louder subwoofers were making isolation more difficult. Specific cinema subwoofer models appeared from , , , Kintek, and in the early 1990s. In 1992, 's six-channel film sound format incorporated a single LFE channel, the "point one" in 5.1 surround sound.

  • In the 2000s, several car audio manufacturers have produced subwoofers using non-circular shapes from manufacturers including Boston Acoustic, Kicker, Sony, Bazooka, and X-Tant. These shapes typically carry some sort of distortion penalties. 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

    Professional audio subwoofers used in rock concerts in stadiums, DJ performances at and similar events must be capable of very high output levels with low distortion. This is reflected in the design attention given in recent years to the subwoofer applications for sound reinforcement, , dance club systems and concert systems. Consumer applications (as in home use) are considerably less demanding due to much smaller listening space and lower playback levels. Subwoofers are now almost universal in professional sound applications such as live concert sound, churches, nightclubs, and theme parks. certified to the standard for playback always include high capability subwoofers. Some professional applications require subwoofers designed for very high sound levels, using multiple 12", 15", 18" or 21" drivers (30 cm, 40 cm, 45 cm, 53 cm respectively). Drivers as small as 10" (25 cm) are occasionally used, generally in horn loaded enclosures.

    Vehicle Specific Subwoofers & Boxes

  • 6.5" Car Subwoofers

    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 enthusiasts compete to produce very high levels in the confines of their vehicle's cabin; sometimes dangerously high. 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 if one is exposed to them for an extended period of time.

Shallow Subwoofer Front View

The end-fire subwoofer method, also called "forward steered arrays", places subwoofer drivers co-axially in one or more rows, using destructive interference to reduce emissions to the sides and rear. This can be done with separate subwoofer enclosures positioned front to back with a spacing between them of one-quarter wavelength of the target frequency, the frequency that is least wanted on stage or most desired in the audience. Each row is delayed beyond the first row by an amount related to the speed of sound in air; typically a few milliseconds. The arrival time of sound energy from all the subwoofers is near-simultaneous from the audience's perspective, but is canceled out to a large degree behind the subwoofers because of offset sound wave arrival times. Directionality of the target frequency can achieve as much as 25 dB rear attenuation, and the forward sound is coherently summed in line with the subwoofers. The positional technique of end-fire subwoofers came into widespread use in European live concert sound in 2006.