Subwoofers were first designed for high-end home audio systems by Ken Kreisel in the 1960s. In the 1970s, subwoofers were installed in movie theatres for movies featuring enhanced "Sensurround" audio. In the late 1970s, after widespread use of the cassette tape caught on, recordings were able to add more low-frequency content because of the cassette's superior ability to reproduce bass. Because of this, use of subwoofers in home audio systems became more popular.
There are two types of subwoofers: passive and active. Passive subwoofers are powered by an external power amp, whereas active subwoofers have a built-in amplifier. A subwoofer's frequency range typically spans from 20 Hz to 200 Hz. Subwoofer speakers normally range from 8" to 21" in size, with the most popular sizes being 10", 12", 15" and 18".
A subwoofer supplements the bass response of a speaker system, allowing the other speakers to be smaller without losing bass response. Since bass frequencies have a long wavelength, subwoofers are omni-directional and can be placed anywhere in the room, without disrupting the perception of an audio system's sound stage.
Home audio and car stereo systems are of the most popular consumer uses for subwoofers. Home audio enthusiasts often invest in a subwoofer when high levels of low bass are desired for home theatre or music playback.
When deciding on the placement of the subwoofer of a home audio system, place it in the corner of the room away from large openings. This will allow for greatest efficiency and best coupling to the room's air volume.
In car stereo systems, it is difficult to fit large subwoofers into the cabin of the car. However, since subwoofers are omni-directional, they can easily be placed in the trunk without affecting their performance.
Corporate uses for subwoofers include the sound systems of recording studios, movie theaters and concert venues. The first recording engineer to use a subwoofer in mixing audio was Roger Nichols, who used it in 1973 to mix the Steely Dan album "Pretzel Logic."
Subwoofers, now a staple in cinema sound, are utilized in Dolby Digital's six-channel film surround-sound format to provide spectacular audio.
Professional audio subwoofers, used for concert sound, must be capable of high-output levels, and are now readily found in sound systems of churches, nightclubs and theme parks to provide more powerful music reproduction.