When a source of discrete‐frequency sound is placed in a reverberation room, the sound‐power output depends on the source position and frequency. In addition, the measured sound‐pressure level depends on microphone position. In this paper, some experimental data are presented that are relevant to both the microphone path length required for an accurate determination of the space/time average mean‐square pressure in the room, and the variations of sound‐power output with source position in the room. Based on theoretical and experimental results, some guidelines are proposed for the determination of the sound‐power radiated by discrete‐frequency sources in a reverberation room.