PURPOSE: To obtain information concerning impression of the sound caused from a speaker and to obtain information examining a speaker installing position, etc., by placing a microphone to the position at a prescribed distance interval from the speaker and the center of the speaker in an anechoic room and by relatively shifting the microphone onto the circumference of a circle with the speaker as a center.

CONSTITUTION: After the measurement of energy for a listening area A ends, a system control means 15 supplies the output to a rotation position control means 16. The rotation position control means 16 receives the output, a turn table is successively controlled to the positions of -40°, -50° and -60°, in the position of the respective turn table 2 the end position of a microphone 10 is controlled in the order of 10°, 0° and -10°, 9 points of B11, B10, B12, B21, B20, B22, B31, B30 and B32 are measured and from the average value, operation 43, display 44 and recording 46 of the energy for the 1st reflection area B are executed. According to the method, the information concerning the impression of the sound of the speaker can be obtained and the energy of the backward area C and the 1st reflection area B can be known.