Rated sound reduction index Rw
After determining the sound reduction index R for specified frequencies, the weighted sound reduction index Rw is calculated in accordance with DIN EN ISO 717-1. It is expressed in the unit of measure decibel (dB). For this purpose, the R values determined by measurement are compared with reference values according to EN 717-1. The reference curve is shifted vertically parallel to the ordinate in the measurement diagram in accordance with EN 717-1 until the undershoot of the measurement curve is on average no more than 2 dB. In this case, exceedances are not taken into account. The ordinate value of the shifted reference curve at 500 Hz corresponds to the weighted sound reduction index Rw (so-called “single value”).