DEVICE FOR MEASURING ACOUSTIC CHARACTERISTIC OF LOUDSPEAKER IN ACTUAL SOUND FIELD

摘要

PURPOSE:To obtain a measured data exactly and quickly by adopting the multipoint sound collecting method that uses plural microphones placed at a plurality of locations in the actual sound field and by processing the data by means of a computer. CONSTITUTION:A measured signal, which contains a component of the audio frequency band and is applied to the loudspeaker 6 to be measured, is produced by the white noise generator 1, 1/3 octave band-pass filter 2 that passes the audio frequency component to make the output of generator 2 a pink noise, graphic equalizer 3 that compensates both the peak-deep of the frequency characteristic caused by the degeneracy of natural oscillation of the actual sound field 5 and the damping of energy caused by the sound absorption of the surrounding wall, and the power amplifier 4. The acoustic characteristic is obtained by both plural microphones 7, which are placed at a multiplicity of locations in the actual sound field 5 to collect the reproduced sound of the measured signal, and the data processing means 100 that analyzes frequencies of outputs of the microphones and operates the mean value, which is obtained from the sound pressure Pi of the respective microphones for each frequency, according to the formula (1) (N: number of microphones).