PCB® model 378A04 is a SPECIALTY microphone used to measure extreme low noise. To accomplish this, it has a very HIGH sensitivity. A result of this high sensitivity is that the 3% distortion level is lower than some handheld calibrators and pistonphones output LEVELS and will overload the microphone. A calibrated reference source needs to be used that cannot exceed 100 dB and must be below 5kHz. The CAL200 calibrator with a reference signal of 94 dB at 1 kHz is recommended for model 378A04 calibration.

PCB® model 378A04 is a specialty microphone used to measure extreme low noise. To accomplish this, it has a very high sensitivity. A result of this high sensitivity is that the 3% distortion level is lower than some handheld calibrators and pistonphones output levels and will overload the microphone. A calibrated reference source needs to be used that cannot exceed 100 dB and must be below 5kHz. The CAL200 calibrator with a reference signal of 94 dB at 1 kHz is recommended for model 378A04 calibration.