A connecting device for constructing an arrangement composed of a plurality of loudspeaker boxes hanging beneath one another comprises a length-adjustable spacer rod which is designed to join together two loudspeaker boxes, which are adjacent in the arrangement, in a load-bearing manner. The length-adjustable spacer rod has a first element and a second element which can be fixed in at least two positions which are adjusted in terms of length relative to one another. In this case, at least one of the positions is secured with a closure which can be established and released by rotating the two elements relative to one another.