Use of ‘‘corner microphones’’ for sound power measurements in a reverberation chamber

A comparison was made between acoustic measurements conducted with microphones mounted in the trihedral corners of the 425‐m3 NBS reverberation chamber and similar measurements using microphones located in the room interior, away from the room boundaries. Measurements of broadband and discrete‐frequency sound pressure and of reverberation time were included. It was found that for frequency bands below the 200‐Hz 1/3‐octave band, the difference in sound pressure level between the corner and interior locations was, in general, more than 9 dB. In addition, the variations in the broadband steady‐state sound pressure level and in the reverberation time were much less among the corners than among the interior locations for frequencies below 100 Hz. It is concluded that for the lower frequency bands, use of the corner locations may reduce systematic errors associated with the interference patterns and provide greater measurement precision because of the lower spatial variance.