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2013
Conference Paper
Titel
Sound transmission between rooms - Effect of air inlets and outlets
Abstract
For the correct determination of sound insulation between rooms all acoustic transfer paths have to be taken into account. Thus, it is necessary to consider as well the transfer path of ventilation and air conditioning, as this can reduce the sound insulating effect of the wall construction substantially due to the direct duct connection, which is well known as cross talk. To calculate the cross talk damping, one can follow the approach delineated in VDI 2081. According to this, the transmission loss of each component on the transfer path is accumulated to the total transmission - the sound insulation of the air conditioning path. But for this also the transmission losses of the air passages are required. The following question arises: Is the transmission loss of an air passage in case of the use as inlet (the transfer from the room into the air system) different to the use as outlet (the transfer from the air system into the room)? This is discussed in the following for simple examples by models and measurements. It starts from the view of the air outlet, where the transmission from the duct into the room is considered. Then the point of particular interest, the transmission loss of the air inlet, the transfer from the room into the duct-system, is considered. Subsequently, the transmission lines were merged to the total transfer path for predicting the flanking transmission of air conditioning systems. All measurements and calculations are carried out for the free standing, not wall mounted, configurations.