retains the soundproofing element 2 at its upper edge and is vertically adjustable relative to the retaining component 30 in the direction of the double arrow 36 as explained in detail in fig4 and can be fixed in its respective adjustment in a way further explained by fig4 and thereby forms a tension means for tensing the sheets 4 6 8 that are connected to each other the soundproofing element 2 possesses piping flanges 38 40 42 at its sides and at its upper edge that positively engage in complementary formed grooves in the supports 24 26 or the crossbeam 28 so that the soundproofing element 2 is safely connected to the support construction via a piping groove connection as fig2 shows the stripe shaped connection points 12 extend essentially across the entire height of the sheets 4 6 in such a way that the connecting length 8 connects the sheets 4 6 essentially across the entire height of the sheets 4 6 the soundproofing element 2 possesses a locking means in the area of the fill openings 18 20 which is constructed of a flap 46 that can be folded out that is connected to the second sheet 6 and is attached at its upper edge 44 and as shown in fig2 can be folded out from the drawing level which closes the fill openings facing the viewer in fig2 of the chambers 14 16 positioned next to each other as well as the additional chambers in the locking positioned illustrated in fig2 the flap 46 can be attached to the second sheet 6 by means of a not illustrated velcro closure in the area of their lower ends the chambers possess outlet openings for the filler medium that can be locked by means of screw caps.