The Apparent Sound Reduction Index of a partition can be measured according to the method described by ISO 140-4. In many real situations, alternative methods, like the intensity based method and the vibration velocity based method, could be useful. The paper reports further results of a research project aimed at testing the reliability of the vibration velocity measurement based method. The results of the comparison between the measurement techniques for walls without particular problems (like airborne paths, leakages, etc.) indicate a good agreement between the values obtained, in particular for single number quantities. However the velocity technique is useful in the identification of particular problems of sound transmission, in particular to calculate the contribution of the flanking transmission from lateral walls. The velocity method is not yet standardized and, at the moment, could be considered as a survey method. The main difficulties are the estimation of the critical frequency for non homogenous walls like hollow bricks walls, the estimation of the radiation efficiency around and below the critical frequency and the obtainment of reliable experimental data at high frequencies due to the drop in the accelerometer’s resonance frequency.
Vibration Velocity Technique for Sound Reduction Index Measurement
FAUSTI, Patrizio;
2003
Abstract
The Apparent Sound Reduction Index of a partition can be measured according to the method described by ISO 140-4. In many real situations, alternative methods, like the intensity based method and the vibration velocity based method, could be useful. The paper reports further results of a research project aimed at testing the reliability of the vibration velocity measurement based method. The results of the comparison between the measurement techniques for walls without particular problems (like airborne paths, leakages, etc.) indicate a good agreement between the values obtained, in particular for single number quantities. However the velocity technique is useful in the identification of particular problems of sound transmission, in particular to calculate the contribution of the flanking transmission from lateral walls. The velocity method is not yet standardized and, at the moment, could be considered as a survey method. The main difficulties are the estimation of the critical frequency for non homogenous walls like hollow bricks walls, the estimation of the radiation efficiency around and below the critical frequency and the obtainment of reliable experimental data at high frequencies due to the drop in the accelerometer’s resonance frequency.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
