Review on 🎛️ Enhanced Precision with the Instruments R8090 Calibrator Diameter Microphones by Bradley Wacks

I have used expensive calibrators and my experience is that this one works just as well as any other. Legal work requires a calibration certificate from B&K or NIST or some other recognized organization, but all my SPL meters are within fractions of a dB of each other. Re: Ambient noise, who cares about half a dB or something? I'm open to learning this.