Static and Dynamic Transmission Losses of Partitions

The conclusions of 10 years of practical experience with a measurement method which the author published earlier [J. Acoust. Soc. Am. 27, 98 (1955)] sum up as follows: Static transmission losses (TL) are defined as the values obtained by standard methods using constant level sounds. Dynamic TL are measured with transients or with varying level sounds. The latter measuring conditions agree much more than the first with practical conditions. TL values measured on traditional types of partitions, (e.g. masonry walls) may vary by ±10 dB from one wall to another of the same type in the same building. For prefabricated partitions, these variations drop to less than ±3 dB. Thus, one sample does not allow us to draw definite conclusions on the TL which should be expected of a type of partition. Three to ten samples should be tested. The time lag of a partition may have a relationship with its sound insulating value. The measurement of the sound TL of any selected partition in any position in a building or a ship ...