To describe the sound reduction index of doors, we often use the parameters Rw,R and Rw,P. Rw,R refers to the required sound reduction index of the installed front door, as opposed to Rw,P, which refers to the index measured in a lab or on a test bay during a sound insulation test. In a lab, however, any bypasses of noise or installation tolerances of the soundproof door cannot be considered. Therefore, the value measured on a test bay Rw,P should be 5 dB higher than the actually required sound reduction index. Rule of thumb: Rw,R = Rw,P - 5 dB.