sentences:  Due to its relatively high efficiency the design is frequently employed in full-range loudspeaker designs.The concept is that the sound emitted from the rear of the loudspeaker driver is progressively reflected and absorbed along the length of the tapering tube, almost completely preventing internally reflected sound being re-transmitted through the cone of the loudspeaker.The lower part of the pipe acts as a horn while the top can be visualized as an extended compression chamber.