Updated: Oct 30, 2022
What we usually consider as impossible are simply engineering problems... there's no law of physics preventing them. - Michio Kaku
Conventional wisdom states that in order for a speaker to efficiently produce music, especially bass, the speaker driver must be in some sort of baffle. The sound coming from its rear wave should not cancel out the sound from the front wave.
This generally takes the form of a speaker cabinet, often a rectangular box made of wood, sometimes chided as a "monkey coffin".
Cabinet types are have an important acoustic role determining the resulting sound quality and bass response. There are several cabinet types available and one that eliminates the cabinet entirely!
1. Sealed cabinet or acoustic suspension.
PROS: easiest and least expensive to build, slow roll off of bass below tuning frequency of cabinet.
CONS: Usually larger cabinets are needed to produce deeper bass.
2. Vented, bass reflex or ported cabinet.
PROS: deeper bass that sealed cabinets, relatively easy to build, nice compromise between considering size of cabinet and cost/complexity.
CONS: faster roll off below tuning frequency, requires careful measurement of port length.
Used in our Hiro 6.5
3. Horn loaded speaker cabinet.