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


The G.R.A.S. 90CA Microphone Calibration System provides for automated and reliable level and frequency response calibration of measurement microphones. The implemented calibration methods conform with these standards:

  • IEC Standard 61094-6
  • ANSI S1.10 – 1966 (R1976)
  • IEC Standard 60942
  • TEDS Standard IEEE 1451.4

The 90CA is PCI-based, with a standard PC and PCI cards for Control and Data Acquisition. The equivalent PXI-based version is G.R.A.S. 90CA-S2.


  • 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 standard microphone sets
  • G.R.A.S. 47xx series flush-mount microphone sets (optional)
  • G.R.A.S. preamplifiers
  • Calibration up to 92 kHz (optional up to 200 kHz)

The system is described in more detail in the Product Data sheet and the Instruction Manual.


ANSI standard S1.10
IEC standard 61094-6

G.R.A.S. Sound & Vibration reserves the right to change specifications and accessories without notice.

Included items

G.R.A.S. HW1000

PCI: System Controller, including: NI Dynamic Signal Acquisition Board PCI-4461 and National Instruments Digital I/O PCI-6503

G.R.A.S. SW0013

National Instruments software Diadem version 10.2 (or later), Base Edition

G.R.A.S. SW0002

Calibration System Software for 90CA

G.R.A.S. SW0012

National Instruments Sound and Vibration Analysis SW Run-Time License 779875-01

For Level Calibration

G.R.A.S. AL0017

Pistonphone Calibration Stand

G.R.A.S. 42AP

Intelligent Pistonphone, including RS-232 control cable

G.R.A.S. 26AN

¼” LEMO Insert Voltage Preamplifier

G.R.A.S. 26AG

½” LEMO Insert Voltage Preamplifier

For Frequency Calibration

G.R.A.S. 26AB

¼” LEMO Preamplifier with Inline Barrel Adapter AF0008 for ¼” preamplifier and ½” microphone

G.R.A.S. 26AK

½” LEMO preamplifier (for use with most non-G.R.A.S. microphones)

G.R.A.S. RA0014

½” Electrostatic actuator (includes ¼” microphone adapter RA0017)

G.R.A.S. AL0010

Actuator Calibration Stand

G.R.A.S. AL0021

Microphone Set Calibration Stand

G.R.A.S. 14AA

Electrostatic Actuator Amplifier, including 230 V AC power cable

For Power, Signal Conditioning and Switching

G.R.A.S. 12AQ

2-Channel CCP/LEMO Power Module with Signal Conditioning and Computer Interface

G.R.A.S. RA0192

Control box (no cables included in the box)

G.R.A.S. 40AG

½” Pressure microphone for reference

Cables, Connectors, Adapters and Tools

G.R.A.S. AA2006

National Instruments Cable 180524-10 (50-position ribbon cable)

G.R.A.S. AA0033

1 m BNC cable (5 pcs)

G.R.A.S. AA0008

3 m LEMO extension cable (3 pcs)


BNC T-connector

G.R.A.S. RA0003

Straight adapter for ½” microphone and ¼” preamplifier

G.R.A.S. RA0063

⅛ microphone and ¼” preamplifier adapter


½” microphone tool


¼” microphone tool


⅛” microphone tool



G.R.A.S. license for SW0002


90CA Instruction Manual


Instruction manuals for 42AP, 12AQ and 14AA


Available Options

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
G.R.A.S. Sound & Vibration reserves the right to change specifications and accessories without notice.