page_title: Subwoofer
section_title: Enclosure designs
hierarchical_section_title: Subwoofer / Applications / Enclosure designs
context_page_description: A subwoofer is a loudspeaker designed to reproduce low-pitched audio frequencies known as bass and sub-bass, lower in frequency than those which can be generated by a woofer. The typical frequency range for a subwoofer is about 20–200 Hz for consumer products, below 100 Hz for professional live sound, and below 80 Hz in THX-approved systems. Subwoofers are never used alone, as they are intended to augment the low frequency range of loudspeakers that cover the higher frequency bands. While the term "subwoofer" technically only refers to the speaker driver, in common parlance, the term often refers to a subwoofer driver mounted in a speaker enclosure, often with a built-in amplifier.
  Subwoofers are made up of one or more woofers mounted in a loudspeaker enclosure—often made of wood—capable of withstanding air pressure while resisting deformation.
context_section_description: Front loaded subwoofers have one or more subwoofer speakers in a cabinet, typically with a grille to protect the speakers. In practice, many front-loaded subwoofer cabinets have a vent or port in the speaker cabinet, thus creating a bass reflex enclosure. Even though a bass reflex port or vent creates phase delay, it adds SPL, which is often a key factor in PA and sound reinforcement system applications. As such, non-vented front-firing subwoofer cabinets are rare in pro audio applications.
  Horn-loaded subwoofers have a subwoofer speaker that has a pathway following the loudspeaker. To save space, the pathway is often folded, so that the folded pathway will fit into a box-style cabinet. Cerwin-Vega states that its folded horn subwoofer cabinets, "...on average, produce 6 dB more output at 1 watt than a dual 18" vented box" giving "four times the output with half the number of drivers."  The Cerwin Vega JE-36C has a five feet long folded horn chamber length in the wooden cabinet.
  Manifold subwoofers have two or more subwoofer speakers that feed the throat of a single horn. This increases SPL for the subwoofer, at the cost of increased distortion. EV has a manifold speaker cabinet in which four drivers are mounted as close together as practical. This is a different design than the "multiple drivers in one throat" approach. An unusual example of manifold subwoofer design is the Thomas Mundorf (TM) approach of having four subwoofers facing each other and sitting close together, which is used for theatre in the round shows, where the audience surrounds the performers in a big circle (e.g., Metallica has used this in some concerts). The TM approach produces an omnidirectional bass sound. Cerwin Vega defines a manifold enclosure as one in which "..the driver faces into a tuned ported cavity. You hear sound directly from the back of the driver in addition to the sound that emanates out of the port. This type of enclosure design extends the frequency capability of the driver lower than it would reproduce by itself.
  Bandpass subwoofers have a sealed cabinet within another cabinet, with the "outer" cabinet typically having a vent or port.
caption: Compound or 4th order band-pass enclosure
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