Patent ID: 7526094

Claim:
An acoustic measurement apparatus for making the microphones of a sound-intensity probe, or of a composite of said probes, have a substantially identical response with a comparison microphone, by determining transfer functions between said microphones and said comparison microphone, including: a normalizer-calibrator tube with a loudspeaker mounted, centered in and closing one axial end of said normalizer-calibration tube; a fixture for holding microphones, mountable in and closing the other axial end of said normalizer-calibrator tube where said microphones are flush with the axial inner surface of said fixture, both microphones in a side by side arrangement facing said loud speaker and simultaneously exposed to plane waves proceeding down said normalizer-calibrator tube from said loudspeaker; said loudspeaker and said microphones connected to an analog-digital converter for conversion of analog signals to digital form and vice-versa; said converter connected to a digital signal processor programmed to normalize and calibrate the signals by determining said transfer functions; and said processor connected to an output device for outputting the results of the computations.