TYPE 9721-A

Microphone Secondary Calibration System

Secondary Calibration System designed for calibration of working standard microphones and other types of microphone.

Demande de devis

Type 9721-A Secondary Calibration System applies the comparison method for sensitivity calibration and the electrostatic actuator method for frequency response calibration.

Type 9721-A is a general-purpose microphone calibration system for calibration of working standard microphones described in IEC 61094-4, laboratory standard microphones described in IEC 61094-1 and other non-standard microphones. The system is intended for calibration service centres and owners of large amounts of microphones. The sensitivity of the microphone is measured by the pressure comparison method described in IEC 61094-5 and the frequency response is measured by the electrostatic actuator method described in IEC 61094-6.


  • Measurement microphone calibration at private and governmental service centres
  • Calibration of microphones (IEC 61094-4, -1 and others) with or without preamplifier
  • Calibration of microphones with or without removal protection grid
  • Calibration of Brüel & Kjær surface microphones


  • Sensitivity calibration by comparison with reference microphone (IEC 61094-5)
  • Sensitivity update of TEDS (Transducer Electronic Data Sheet)
  • Calibration of open-circuit or loaded sensitivity (that is, sensitivity with preamplifier)
  • Frequency response calibration by comparison (IEC 61094-5) 20Hz to 20kHz
  • Frequency response calibration by electrostatic actuator (IEC 61094-6) 20Hz to 100kHz
  • Pressure, free-field and diffuse-field responses by applying corrections
  • Fast, automated measurement, printing of calibration certificate and data export to Excel
  • Detailed operator instructions