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.

GRAS 14AA Electrostatic Actuator Amplifier

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.”..

GRAS 26AG 1/2'' Insert Voltage Preamplifier with Integrated Connector

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...

GRAS 26AN 1/4'' Insert Voltage Preamplifier

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..

GRAS 42AA Pistonphone, Class 1

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...

GRAS 42AB Sound Calibrator, Class 1

Sound pressure level: 114 dB
Frequency: 1 kHz
ANSI: S1.40
IEC: 60942

GRAS 42AB Sound Calibrator, Class 1

The GRAS 42AB  Sound Calibrator is a small 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...

GRAS 42AC Pistonphone, high pressure, Class 1

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. ..

GRAS 42AE Low Frequency Calibrator

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...

GRAS 42AG Multifunction Sound Calibrator, Class 1

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...

GRAS 42AP Intelligent Pistonphone, Class 0

Sound pressure level: 114 dB
Frequency: 250 or 251.2 Hz
ANSI: S1.40
IEC: 60942, Class 0

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...

GRAS 51AB Phase Calibrator according to IEC 61043

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..

GRAS 51AC Sound Intensity Calibration Kit

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...

GRAS 51AC-S1 Sound Intensity Calibration Adapter for 50AI-LP

Standard: IEC 61043
Special feature: Calibration coupler with two matched calibration chambers for the 50AI-LP Rugged Intensity Probe.

GRAS 51AC-S1 Sound Intensity Calibration Adapter for 50AI-LP

The 51AC-S1 Sound Intensity Calibration Adapter is a calibration adapter for sensitivity and phase calibration of the GRAS 50AI-LP CCP Rugged Intensity Probe...