A shallow subwoofer is a special type of subwoofer, which is a speaker driver designed to reproduce only low bass frequencies. They differ from regular subwoofers in that they are designed to fit in narrower spaces than a regular one. This shallow design makes them especially suitable for use in car audio applications where space is at a premium.
Shallow subwoofer drivers operate much like other types of subwoofers in that they convert the musical signal into magnetic waves, which move a cone back and forth, thereby moving the air and creating sound. Typical subwoofers have a conical shape with a long protrusion for the voice coil and magnet. The designer of a shallow subwoofer, on the other hand, will flatten its front surface while using various design techniques to reduce the size of the protrusion on its back panel. Due to this, it is possible for a shallow-design subwoofer to have performance equivalent to a regular subwoofer that is twice the depth of the shallow subwoofer.
The key benefit of the shallow subwoofer is that it opens up additional mounting options for subwoofers. Earlier subwoofers needed to be installed in the trunk of a car, where there would be enough space for their large structures. The invention of the tube subwoofer made it possible to put a subwoofer into tight spaces, such as behind the seat of a regular-car or pickup truck, but that technology produced inferior sound quality. Shallow subwoofers combine a sound that is more akin to a regular subwoofer in a regular enclosure with some of the flexibility of tube-type enclosures.
Car audio enthusiasts can buy a stand-alone shallow subwoofer and combine it with other subwoofer parts, like an enclosure, an amplifier, and mounting hardware to get the best performance. On the other hand, many manufacturers also offer powered subwoofer units that are pre-configured and ready for a simple installation. These make it easy to get good performance with minimal inconvenience. Some powered subwoofers with shallow drivers are small enough to even fit under the seat of a car.
Regardless of whether a car system gets used to play the bass "thump" in rap music, the deep notes of a pipe organ in a Bach fugue, or the explosions in an action movie, it needs a subwoofer to reproduce those frequencies. In the past, good quality subwoofers were only available for cars with a great deal of available space. Thanks to shallow subwoofer technology, car audio enthusiasts can now enjoy bass in just about any car.