Subwoofer boxes, which operate according to the double chamber principle, are generally known in the state of the art, so that a detailed explanation of the operation of such boxes can be omitted.
As explained in detail by DE 41 21 408, double chamber boxes are formed by dividing the outer housing into two spaces by means of a partition wall. Depending on the construction, each opening in the partition wall contains either one or a number of loudspeakers. The sound of the respective loudspeaker radiates through the so-called open volume of the box, which is equipped with a radiation opening for that purpose, and which connects the open volume with the listening space. The other space formed by the partition wall, which is also called a closed volume, is fully separated from the listening space by the loudspeaker, the partition wall and the housing.
To tune such boxes, a so-called bass reflex tube is usually inserted and connected to the radiation opening. If the double chamber box being built has a simple geometric form, it is possible to construct the bass reflex tube and the wall, into which the tube is inserted, in one piece--perhaps by using the injection molding method. However, if double chamber boxes have complicated geometric forms, in accordance with the requirements of many users of such boxes, in most cases it is not possible to form the bass reflex tube and the wall, into which it is inserted, in one piece. In such cases it is necessary to form the bass reflex tube as a separate part, and then attach it to the open volume of the box. This connection of open space and bass reflex tube is not uncritical, since on the one hand a strong connection between tube and wall is required, and on the other the tube must be air-tight against the wall. Due to the production tolerances between the opening in the wall and the outside diameter of the bass reflex tube, it is necessary to take expensive connecting and sealing measures in such cases. Furthermore, the accuracy of the depth of penetration of the bass reflex tube into the open volume must be ensured during installation.
For that reason the invention has the task of presenting a double chamber box that can be produced without great expense, even if the double chamber box has complicated shapes.