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