Measurement of sound transmission loss of floating floors

The sound transmission loss of several materials was measured by using an impedance tube. The impedance tube system designed for the testing consisted of an upstream tube, a sample-holder section and a downstream tube. The transfer function method was used in measuring and calculating the sound transmission loss. Results are presented graphically and compared to each other. Sound reduction index was determined for each material. Three types of existing floors and three types of newly designed floors were tested. From the comparison of sound reduction indices, new floors with indices of 48 dB showed to have poorer sound insulation properties than existing floors with indices up to 55 dB.