Enclosures

Introduction to Speaker Cabinet Design

Bass Reflex – A speaker cabinet also known as ported or vented cabinet is an enclosure that is provided with a vent to allow air to exit from the inside of the enclosure. The port enables the sound from the inside of the enclosure to increase the efficiency of the system at low frequencies. This cabinet is designed for maximum output but sacrificing the sound quality. This increase in efficiency comes with flaws, this enclosure can have poor transient response and the lack of dynamics with recorded music without the use of a subs.

Front Loaded Horn – A loudspeaker that uses a horn flare in front of the speaker element to increase the overall efficiency of the speaker element. The result is greater acoustic output from a given driver. Horns add considerable acoustic gain to the driver resulting in a loudspeaker of much higher efficiency than conventional designs. As a result, horn speakers are quite common in the world of sound reinforcement where high decibel levels are more important than high fidelity.

Rear Loaded Horn – A loudspeaker that uses a horn flare to vent the rear of the speaker element to increase the overall efficiency of the speaker element. The result is greater acoustic output from a given driver. Horns add considerable acoustic gain to the driver resulting in a loudspeaker of much higher efficiency than conventional designs. As a result, horn speakers are quite common in the world of sound reinforcement where high decibel levels are more important than high fidelity.

Folded Horn – A concept that is the same as the front loaded horn with the exception that the length is greater due to the bending of the flare inside the speaker enclosure. For equivalent output levels, a horn-loaded driver undergoes significantly reduced excursion from a directly air-loaded competitor. Ten to 15dB of acoustical gain means that, everything else being equal, a horn-loaded transducer never abandons its area of linearity — even at high levels. The increased efficiency of horn loading naturally requires lower power levels and a speaker sensitivities in upper 90s or low 100s.

W-Bin – A concept of a front loaded horn that uses a horns on each side of the speaker element. This would be the same as using a two single folded horn cabinet design setting side by side but designed into one cabinet and using one speaker element.

BandPass – A chambers ported enclosure with the speaker element mounted on a baffle between two of the internal chambers. As implied, the bandpass design exhibits both low- and high-frequency roll offs of 12 dB/octave achieving a typical response of 40 – 120 Hz.

Tapped Horn – This concept is provided to minimize the size of the enclosure and still provided the response that a larger horn would provide. The front of the speaker is facing the throat of the horn with the back side ported within the mouth of the horn. The outputs of both paths combine in phase to give a result of as much as 6 dB increase in efficiency while minimizing the distortion.

Transmission Line Loudspeaker – This enclosure design uses what is called an acoustic transmission line within the cabinet. The sound is directed through dampened path within the enclosure, which acts as an acoustic waveguide, is used to absorbed or reduce the undesirable effect generated within the enclosure. This design typically provide exceptionally high fidelity response at low frequencies and is less sensitive to positioning for live application. This design avoids many of the major disadvantages of other loudspeaker designs and can provides an increase in gain of about 4dB.

Line Array – A loudspeaker system that is made up of a number of elements coupled together in a vertical line segment to create a near-line source of sound. The distance between adjacent drivers are close enough that they constructively interfere with each other to send sound waves farther than traditional horn-loaded speakers and with a more evenly distributed sound output pattern. Adding horn technology would increase efficiency of the drivers and power requirement would decrease.