Car Subwoofers & Enclosures

A subwoofer is a type of loudspeaker dedicated to the reproduction of bass frequencies, typically from about 20 Hz to about 200 Hz and in the case of a rotary woofer, from 20Hz down to DC. more...

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It is difficult for small loudspeakers to reproduce frequencies below 40 Hz, especially above 100 dB, and so it is often advantageous to use a loudspeaker intended specifically for this task.

History

The first commercial subwoofer was developed during the 1970s by Ken Kreisel, current president of M&K Sound/Miller & Kreisel Corporation in Los Angeles. Kreisel's business partner, Jonas Miller, owned a high-end audio store in Los Angeles, and customers of some of the highest quality electrostatic speakers complained about a reduction of bass response in the electrostatics, compared to conventional loudspeakers; Kreisel's solution was to design a powered loudspeaker that would reproduce only those frequencies that were too low for the electrostatic speakers to convey and thereby fill in the missing sonic information. The first known use of a subwoofer in a recording session was for the mixing of the Steely Dan album Pretzel Logic when recording engineer Roger Nichols arranged for Kreisel to bring a prototype of his subwoofer to Village Recorders. Further design modifications were made by Kreisel over the next ten years (and continuing to the present day), and in the 1970s and 1980s by engineer John P. D'Arcy; record producer Daniel Levitin served as a consultant and "golden ears" for the design of the crossover network (used to partition the frequency spectrum so that the subwoofer would not attempt to reproduce frequencies that were too high for its effective range, and so that the main speakers would not need to process frequencies that were too low for their effective range).

Overview

Subwoofers use drivers (woofers) typically coming in sizes between 8" and 15", but can be as large as 34". Some drivers as small as 4" may be referred to as subwoofers but drivers less than 8" generally do not have the size and excursion necessary to produce lower frequencies well . The most common subwoofer sizes in professional audio are 15" and 18".

Larger cone diameters tend to be advantageous because low frequencies involve moving a great deal of air. A recent trend has been for high excursion. Excursion is defined as how far the cone can linearly travel from its resting position. Some newer models can move as much as +/-2.5" , yielding an overall controlled displacement of 5" with the voice coil of the driver staying inside the magnetic field.

Subwoofers are usually powered by a high power amplifier, and often an electronic crossover with a Low-pass filter is used to ensure that higher frequencies will not be directed to the subwoofer. Subwoofers which include an amplifier in the subwoofer cabinet are called "active" or "powered" subwoofers, while those lacking the built-in amplifier are "passive" subwoofers.

Read more at Wikipedia.org