Subwoofers are arranged in a quite peculiar way and have unique features. Subwoofers are set in separate compartments that cover about a three-octave range. The large wave-range within the subwoofer range might diffract around close objects, typically other subwoofer speakers. While full-range speakers are usually not faced directly toward each other, subwoofers find that assembly practical and beneficial for the produced sound.
Subwoofers can fall under two categories: omnidirectional and cardioid. The omnidirectional version is not considered truly omnidirectional. The cardioid version involves front and backfiring drivers that use face offset to create a coupling area a the front and a cancelling area at the back. It’s worth mentioning that, although cardioid subwoofers have many advantages, they also produce a rear rejection over a wide frequency range. Subwoofers can also be classified as active subwoofers and passive subwoofers. Active subwoofers involve a build-in amp whereas passive subwoofers consist of an external amplifier.
The first subwoofer speakers were developed to add bass response to home stereo systems. The first version of a subwoofer was launched around 1960 and became quite popular around 1970, with the introduction of Sensurround in movies. These were able to produce loud low-frequency sounds through large subwoofers. With the 1980s came the cassette and the compact disc, making the reproduction of deep and loud bass quite simple, so producers could add more low-frequency content to recordings. In the 1990s the surround sound process was invented and highly used. This process involved a low-frequency effects channel, also known as LFE channel which could be heard with a subwoofer integrated into home theatre systems. Around the year 2000, subwoofers became extremely popular within nightclubs and live concerts.
Subwoofers are usually set inside wood or plastic loudspeaker box. There are several varieties of subwoofers, including bass reflex, horn-loaded, bandpass and infinite baffle subwoofers. The difference between them relies on their efficiency, size, cost, power handling, and distortion.
The right setup is required for DJ’s, bands, and singers to achieve a high-quality sound system. This setup includes subwoofers, woofers, tweeters, and mid-ranges that are able to handle a wide range of notes and sounds. The frequency range of a subwoofer depends entirely on its use. The frequency of a subwoofer for home-use is set between 20Hz and 200Hz, whereas a subwoofer designed for professional use sound is set below 100Hz.