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A loudspeaker enclosure or loudspeaker cabinet is an enclosure in which speaker drivers and associated electronic hardware, such as crossover circuits and amplifiers, are mounted. Enclosures may range in design from simple, rectangular particle-board boxes to very complex cabinets that incorporate composite materials, internal baffles, horns, ports and acoustic insulation. The primary role of the enclosure is to prevent sound waves generated by the rearward-facing surface of the diaphragm of an open driver interacting with sound waves generated at the front of the driver. Because the forward- and rearward-generated sounds are out of phase with each other, any interaction between the two in the listening space creates a distortion of the original signal as it was intended to be reproduced. Additionally, because they would travel different paths through the listening space, the sound waves would arrive at the listener's position at slightly different times, introducing echo and reverberation effects not part of the original sound. The enclosure also plays a role in managing vibration induced by the driver frame and moving airmass within the enclosure, as well as heat generated by driver voice coils and amplifiers (especially where woofers and subwoofers are concerned). Sometimes considered part of the enclosure, the base may include specially designed "feet" to decouple the speaker from the floor. == History == Early on, radio loudspeakers consisted of horns, often sold separately from the radio itself, (typically a small wood box containing the radio's electronic circuits〔Illustrations () Retrieved November 26, 2012.〕), so they were not usually housed in an enclosure.〔Illustrations (), Retrieved November 26, 2012.〕 When paper cone loudspeaker drivers were introduced in the mid 1920s, radio cabinets began to be made larger to enclose both the electronics and the loudspeaker.〔Illustrations () Retrieved November 26, 2012.〕 These cabinets were made largely for the sake of appearance, with the loudspeaker simply mounted behind a round hole in the cabinet. It was observed that the enclosure had a strong effect on the bass response of the speaker. Since the rear of the loudspeaker radiates sound out of phase from the front, there can be constructive and destructive interference for loudspeakers without enclosures, and below frequencies related to the baffle dimensions in open-baffled loudspeakers (described in Background section, below). This results in a loss of bass and comb filtering (i.e. response peaks and dips in power regardless of the signal meant to be reproduced). Before the 1950s many manufacturers did not fully enclose their loudspeaker cabinets; the back of the cabinet was typically left open. This was done for several reasons, not least because electronics (at that time tube equipment) could be placed inside and cooled by convection in the open enclosure. Most of the enclosure types discussed in this article were invented either to wall off the out of phase sound from one side of the driver, or to modify it so that it could be used to enhance the sound produced from the other side. However, a few designs have ventured in a different direction, attempting to incorporate the natural acoustic properties of the cabinet material rather than deaden it, and shape the cabinet so that the rear can remain open and still provide good bass response with limited comb filtering.〔Auditorium 23 (), Retrieved November 26, 2012.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Loudspeaker enclosure」の詳細全文を読む スポンサード リンク
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