ABSTRACT
The advantage of anechoic room measurements is that a directivity pattern can be obtained (see also the discussion on sound radiated from the housing).
The second type of room is the reverberation room. It is designed (rigid walls) to reflect nearly all of the radiated sound. In principle, this should allow us to obtain the same sound power level anywhere in the room. Therefore, a single measurement of the compressors will be sufficient. Compressors can be theoretically compared to each other with a single sound power level number, while a comparison of different compressors in an anechoic room setting requires an integration of all the sound pressure levels on a sphere with the compressor at its center.
