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 intensity based method and vibration velocity based method, could be useful. The paper reports the preliminary results of a research project aimed to test the reliability of the vibration velocity measurements based method. The results of the comparison between the measurement techniques indicate a good agreement between the values obtained, in particular for single number quantities. 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 wall. Measurement is possible also during the construction, in particular when there are problems of transmission due to leakages or air ducts or paths. The 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-homogeneous walls like hollow bricks walls and the estimation of the radiation factor around and below the critical frequency.