The Pistonphone is a precision sound source for calibrating microphones.
 

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.
 

Click on images for details:

Sound Calibrator
Type 42AB Portable, battery operated calibrator, produces constant sound pressure level of 114 dB re. 20µPa (equivalent to 10 Pa) at 1 kHz
Pistonphones
Type 42AA Portable, battery operated, produces constant sound pressure level of 114 dB re. 20µPa (equivalent to 10 Pa) at 250 Hz, or 105.4 dBA re. 20µPa (within 0.1 dB)	Type 42AC Portable, battery operated, produces constant sound pressure level 134 dB re. 20µPa (equivalent to 100 Pa) at 250 Hz, or 125.4 dBA re. 20µPa (within 0.1 dB).
Type 42AP Portable, battery operated, produces constant sound pressure level of 114 dB re. 20µPa (equivalent to 10 Pa) at 250 Hz or 251.2Hz, With built-in precision barometer & thermometer + additional capabilities
Intensity Microphone Calibration
Type 51AB Coupler for phase response calibration of microphone pairs used for measuring sound intensity
Microphone Calibration System
Type 90CA Complete Microphone Calibration System. Allows you to do it in Four Easy Steps: (i) Microphone Registration, (ii) Level Calibration, (iii) Frequency Calibration, and (iv) Print Calibration Certificate
Low Frequency Calibrator
Type 42AE Allows microphone calibration at frequencies down to 0.01 Hz for both front and rear-vented microphones
Electrostatic Actuators
Type 14AA - Actuator Power Supply High-voltage, high-gain amplifier and voltage supply for driving electrostatic actuators. The high-voltage output can also be used to drive standard microphones as sound sources.
RA0014 Electrostatic actuator for testing frequency response of 1/2" and 1/4" (using included adapter) microphones.	RA0015 Electrostatic actuator for testing frequency response of 1" microphones.
Calibration Stand
AL0010 Convenient platform for testing condenser microphones

 
Want to learn more or place an order?     Contact us.
 

Other G.R.A.S. Sound and Vibration products

• Microphones
• Preamplifiers
• TEDS Microphones
• Power Modules
• Intensity microphones and calibrators
• Intensity Probes
• Telephone test head
• KEMAR Manikins - Types 45BM and 45BA
• Artificial ears, ear & mouth simulators
• Accessories
• Handset Positioning System - Type 45EA