dur-SONIC CUBE was developed to fulfil acoustic requirements in rooms with open ceilings [for example: open cell ceilings, expanded metal ceilings, LOOP]. The attainable sound absorption effect depends on the density of the elements deployed. Due to the high absorbency of a single dur-SONIC CUBE element a good effect can already achieved at low densities. NRC-values of up to 0,85 can be obtained. Thereby a rigid arrangement of the elements is not necessary. The elements can be placed unobtrusively wherever there is room to be found in the ceiling void.