On the subject of sound insulation, we would like to clarify the terms relating to our loudspeakers. Unfortunately some protection properties are wrongly declared on the market. For example, a rear mounted backbox is an effective reduction of the airborne sound emitted from the loudspeaker to the rear, but it is not sound decoupling.


These are components that are supposed to insulate something. Thus, the thermal insulation usually insulates the heat loss at the outer facade. Sound insulation reduces the airborne noise of a structural cavity in lightweight walls or suspended false ceilings. In the case of impact sound insulation, the structure-borne noise between the screed and the raw ceiling should be reduced. It is important to know that only porous and flexible materials reduce airborne noise. Foamed polystyrene is a good protection for heat transmission, but as a rigid material it cannot be used optimally for sound insulation.


The aim is to decouple components with respect to structure-borne noise. This is done with spring elements or permanently elastic joints. An example of this is the suspended drywall ceiling or edge strips on the screed, which itself floats and does not transmit the impact sound (also structure-borne sound) to the ceiling underneath or the adjacent wall. As the invisible loudspeaker is connected to the adjacent wall and/or ceiling surface in a force-locking manner (screws) + material-locking manner (filler), a transmission of structure-borne sound takes place in any case. With some cerasonar models this is even desirable. Only the excited larger vibrating area of the 1520×1 panel increases the frequency range towards the low tones.


It is therefore highly recommended for multi-family buildings to install the invisible loudspeakers in a decoupled level – for example in a suspended ceiling. In the case of single-family houses, this is due to personal requirements. Because in case of doubt one only disturbs oneself – or listens to the music in the neighbouring room that one has chosen oneself.

With a separate wall construction, the sound remains in the music zone:

In the measurement on the right side you can see two frequency curves of an invisible loudspeaker (no Cerasonar) which was built into the solid wall. In the adjoining room with the “orange” measuring line, only 10 dB is reduced at the same time, audible as in the room where music is actually heard > see “green” measuring line.Source: