Similar to the GA601 in design, the GA607 meets the demanding standards of a class 1 calibrator. It features two calibration levels, 94dB and 104dB re 20µPa both at 1kHz. It is for use with 1/2” microphones. Using the GA607, a sound level meter can be checked at two meter scale points and usually on two ranges.

IEC 60942 states that for a calibrator to be used in the Class 1 category, it must be corrected for barometric pressure. The Castle GA690 barometer is supplied with the GA607 Class 1/C calibrator for just this purpose. With a simple readout on the clear display and a correction table printed on the reverse, this is a simple process.