Calibration equipment
Calibration is an essential step in every precision measurement. It establishes the relationship between the sound pressure and the electrical output of the microphone.
Calibration can be performed at either 250 Hz or at 1 kHz. Both frequencies have their advantages and disadvantages.
250 Hz is in the frequency range where the frequency response of almost all microphones is flat and will therefore give the most accurate calibration.
If, however, the microphone is used in connection with measuring equipment with weighting filters, for example a sound level meter with A-weighting, the 250 Hz signal will be attenuated by the weighting network. In this case it might be advantageous to use a 1 kHz calibration frequency.
At 1 kHz, the weighting filters have 0 dB attenuation and will therefore not affect the calibration.
On the other hand, since the frequency response of the microphone is not flat, a small error could be introduced.
Freq range: 1 Hz to 200 kHz
IEC: 61094-6
GRAS 14AA Electrostatic Actuator Amplifier
The GRAS 14AA Electrostatic Actuator Amplifier is a high-gain, high-voltage amplifier. The 14AA together with the available GRAS electrostatic actuators RA0014 and RA0015 comply with IEC 61094 -6 “Measurement microphones - Part 6: Electrostatic actuators for determination of frequency responses.”..
Freq range: 2.5 Hz - 200 kHz
Noise: 1.8 µV
Gain: -0.25 dB
Special feature: Insert voltage for determining open-circuit sensitivity of a microphone
GRAS 26AG 1/2'' Insert Voltage Preamplifier with Integrated Connector
The GRAS 26AG is a small robust preamplifier with insert voltage calibration facility. It has a very low inherent noise level, a wide dynamic range and a frequency response from below 2 Hz to above 200 kHz...
Freq range: 2.5 Hz - 200 kHz
Noise: 1.8 µV Gain: -0.29 dB
Special feature: For open-circuit sensitivity calibration of 1/2" and 1/4" microphone cartridges
GRAS 26AN 1/4'' Insert Voltage Preamplifier
The GRAS 26AN 1/4" Preamplifier is a small robust unit optimised for acoustic measurements using condenser microphones. It has a very low inherent noise level, a wide dynamic range and a frequency response from below 2 Hz to above 200 kHz.GRAS 26AN is configured to permit use of the insert..
Sound pressure level: 114 dB
Frequency: 250 Hz
IEC: 60942
GRAS 42AA Pistonphone, Class 1
The GRAS Pistonphone 42AA is a battery-operated, precision sound source for accurate and reliable calibration of measurement microphones, sound level meters, and other sound measuring equipment...
Sound pressure level: 134 dB
Frequency: 250 Hz
ANSI: S1.40
IEC: 60942
GRAS 42AC Pistonphone, high pressure, Class 1
The GRAS 42AC Pistonphone, high pressure is a precision sound source for calibrating microphones. It is battery operated and produces a constant sound pressure level of 134 dB re. 20µPa (equivalent to 100 Pa) at 250 Hz, or 125.4 dBA re. 20µPa. ..
Sound pressure level: 140 dB
Freq range: 0.01 to 250 Hz
GRAS 42AE Low Frequency Calibrator
The GRAS 42AE Low-Frequency Calibrator permits microphone calibration at frequencies down to 0.01 Hz for both front and rear-vented microphones. It produces a constant sound pressure level down to very low frequencies...
Sound pressure level: 94 dB or 114 dB
Frequency: 250 Hz or 1 kHz
ANSI: S1.40
IEC: 60942 class 1
GRAS 42AG Multifunction Sound Calibrator, Class 1
The GRAS 42AG Multifunction Sound Calibrator is a portable, battery-operated precision microphone calibrator. The calibrator can be used directly on 1" microphones. Adapters for calibrating 1/2" (factory mounted), 1/4" and 1/8" microphones are included...
Sound pressure level: 114 dB
Frequency: 250 or 251.2 Hz
ANSI: S1.40
IEC: 60942 (2018) LS
GRAS 42AP Intelligent Pistonphone Class 0
The GRAS 42AP Pistonphone is a battery-operated, precision sound source for accurate and reliable calibration of measurement microphones, sound level meters and other sound measuring equipment...
Freq range: 50 Hz to 6.3 kHz
ANSI: S1.10
IEC: 61043
GRAS 51AB Phase Calibrator according to IEC 61043
The Sound-intensity Calibrator 51AB is a coupler for phase and level calibrations of sound-intensity microphone pairs. It can be used for residual intensity testing, sound-intensity level calibration and particle velocity calibration as specified in IEC standard 1043 Electroacoustics-Instruments for..
Standard: IEC 61043
Special feature: Calibration coupler with two matched calibration chambers for GRAS Rugged Intensity Probes.
GRAS 51AC Sound Intensity Calibration Kit
The 51AC Sound Intensity Calibration Kit is a ready to use kit for sensitivity and phase calibration of GRAS Rugged Intensity Probes (50AI-LP, 50GI-P, 50GI-RP). The kit consists of a calibration adapter with two calibration chambers, a GRAS 42AA Pistonphone, Class 1, and a GRAS ZC0002K Barometer...
Freq range:
ANSI: S.1.40, S.1.43, S.1.11, S.3.6
IEC: 60318-1 & -2
GRAS 90AA Audiometer Calibration System
The GRAS 90AA Audiometer Calibration System is easy and fast to set up and control and can be upgraded as your calibration needs change. From quick measuring of frequencies and test signal levels to harmonic distortion and representation of the values in one table together with the third octave band..
Freq range:
ANSI: S.1.40, S.1.43, S.1.11, S.3.6
IEC: 60318-1 & -2
GRAS 90AB Basic Audiometer Calibration System
The GRAS Audiometer Calibration Systems are configured to meet the requirements of modern audiometer calibration. They are easy and fast to set up and control, and can be upgraded as your calibration needs change...
