Fiberglass subwoofer enclosures are unique to the speaker box industry since they can be constructed in any shape desired, such as sealed, ported, or bandpass types. The fiberglass fabrication process entails mixing resin with tiny glass strands, and allowing it to dry into a predetermined form. Some DIY craftsmen form fiberglass subwoofer enclosures from scratch for a personalized support shape, whereas other consumers may purchase a manufactured enclosure at a local audio retail store.
Sealed fiberglass subwoofer enclosures are the most common and simple speaker support. The enclosure has one circular opening for the subwoofer's sound output, confining the remaining rear speaker portion to a closed space. Sound waves vibrate within the sealed box area, producing an all around steady sound appropriate for multiple music genres.
Ported fiberglass subwoofer enclosures use a strategically placed tube for directing sound waves outward from the speaker's rear area. Bass sounds are stronger, making it a desirable support box for playing rock and roll. Strong fiberglass braces the walls to prevent reverberation that can inhibit a pleasing bass output.
The bandpass subwoofer enclosure is a more complex structure, and works well with the versatile fiberglass material. Multiple ports are specially designed either to the front or rear of the subwoofer, moving the pulsing sound waves in numerous directions for the most extreme bass boom. Unique fiberglass shapes can be created in a number of different curves and ports for conforming to a car trunk or corner of a room.
The versatility and strength of fiberglass makes it a practical choice for enclosure creation. Many oddly shaped enclosures use fiberglass as the main structural support, rather than using fiberboard or wood paneling. Enclosures that conform to the shape of a car trunk tend to be curved and rounded for an aesthetically pleasing appearance. The use of fiberboard would make this enclosure type practically impossible.
In contrast, some fiberglass subwoofer enclosures use a combination of fiberglass and fiberboard for a very strong support box. Less manufacturing time is needed to dry the fiberglass structure since the glass strand and resin thickness is reduced by the fiberboard core. Many DIY craftsmen find this construction easier to build, compared to a strictly fiberglass enclosure.
DIY enclosure construction with fiberglass is an especially tedious process, requiring attention to thickness along the entire structure. Larger enclosures should have thicker fiberglass walls to allow them to retain their shape during stressful sound vibrations. Smaller and more compact enclosures do not need as thick a structure since the attached subwoofer would be small, generating less bass boom.