G.R.A.S. 90CA Microphone Calibration System

Freq range:
ANSI: S.1.10
IEC: 60318-1 & -2

Microphone Calibration in Four Easy Steps:

  • Microphone Registration
  • Level Calibration
  • Freqency Calibration
  • Print Calibration Certificate


  • Ready-to-use software and hardware
  • Accurate calibration hardware
  • Automated and computer-controlled calibration process
  • Highly reproducible calibration method
  • Pre-installed test parameters for G.R.A.S. microphones
  • Test conditions easily changable
  • Auto-generated, customized documentation to print and archive


  • All types of IEC 61094 standardized 1", 1/2", 1/4", and 1/8" measurement microphones from G.R.A.S. and other manufacturers
  • G.R.A.S. 46xx series microphone sets
  • G.R.A.S. 47xx series microphone sets (optional)
  • G.R.A.S. preamplifiers
  • Calibration up to 92 kHz (optional up to 200 kHz)
Frequency range (±1 dB) Hz TBD
Sound pressure level dB TBD
Power supply, external Vdc TBD
Input signal, max. Vrms TBD
AC output Vrms TBD
Actuator output Vdc TBD
Microphone polarization output Vdc TBD
AC output impedance TBD
Actuator output impedance TBD
Microphone polarization output impedance TBD
Gain dB TBD
ANSI standard S1.10
IEC standard 60318-1 & -2 (former 60318)
Temperature range, operation °C / °F TBD / TBD
Battery type TBD
CE/RoHS compliant/WEEE registered No/
Weight g / oz / TBD

Special options are available for specific types of calibration, accredited calibration, and training.

G.R.A.S. OP0020:

  • Preamplifier Calibration Option
  • 1/2" Pressure microphone, prepolarized
  • 1/4" Preamplifier with 3 m cable
  • 1/2" CCP preamplifier
  • 1/4" CCP preamplifier with 3 m cable (Microdot connector)
  • 20pF Input adapter for ½’’ preamplifiers
  • 3 m microphone cable, SMB-BNC connector
  • 1 m Cable BNC 50 ohm
  • Test program for preamplifier

G.R.A.S. OP0021

  • Calibration of 1” Microphone Option
  • Adapter for 1” microphone and 1/2" preamplifier
  • 1” Electrostatic actuator

G.R.A.S. OP0022

  • Accredited Calibration of Reference Units
  • DANAK calibration of reference microphone, reference preamplifier, and pistonphone

G.R.A.S. OP0023

  • Kit for sensitivity calibration of Flush-mount microphone Sets

G.R.A.S. OP0024

  • Kit for frequency calibration of Flush-mount microphone Sets

G.R.A.S. OP0025

  • Kit for sensitivity calibration of Surface microphone Sets

G.R.A.S. OP0026

  • Kit for frequency calibration of Surface microphone Sets