GRAS 40BE-FV 1/4" Prepolarized Free-field Microphone, Front Vented
Freq range: 4 Hz to 80 kHz
Dyn range: 30 dB(A) to 168 dB
Sensitivity: 4 mV/Pa
Technology
Introduction
It is a high-precision condenser microphone made according to IEC 61094-4 requirements. Its dynamic range makes it suitable for high-frequency or high-level measurements, as well as acoustic transient measurements. It is extremely robust and reliable and can measure sound pressure levels up to 168 dB in the range of 4 Hz to 100 kHz.
40BE-FV is individually factory-calibrated and delivered with a calibration chart stating its specific open-circuit sensitivity and pressure frequency response.
NOTE: At low frequencies, protection grids are acoustically transparent; however, around 20 kHz and above, protection grids can act as resonators and influence the frequency response. So for higher frequency measurements, ¼″ and ⅛″ microphones have been optimized for use without the protection grid. Please remove the protection grid when measuring.
Typical applications and use
The 40BE-FV is ideal for sound measurements at very high frequencies and levels, as well as acoustic transient measurements. It is suitable for general purpose measurements in open acoustic fields.
Compatibility
The 40BE-FV requires a standardized 1/2" or 1/4" CCP preamplifier and an input module that supports this technology with a BNC, SMB, or Microdot connector.
System verification
For daily verification and check of your measurement setup, we recommend using a calibrator like GRAS 42AG Sound Level Calibrator.
For proper sensitivity calibration, we recommend using a pistonphone like GRAS 42AP Intelligent Pistonphone.
Quality and warranty
All GRAS microphones are made of high-quality materials that will ensure life-long stability and robustness. The microphones are all assembled in verified clean-room environments by skilled and dedicated operators with many years of expertise in this field.
The microphone diaphragm, body, and improved protection grid are made of high-grade stainless steel, which makes the microphone resistant to physical damage, as well as corrosion caused by aggressive air or gasses.
This, combined with the reinforced gold-plated microphone terminal which guarantees a highly reliable connection, enables GRAS to offer 5 years warranty against defective materials and workmanship.
Service
If you accidentally damage the diaphragm on a GRAS microphone, we can—in most cases—replace it at a very reasonable cost and with a short turn-around time. This not only protects your investment, but also pleases your quality assurance department because you don’t have to worry about new serial numbers, etc.
Calibration
Before leaving the factory, all GRAS microphones are calibrated in a controlled laboratory environment using traceable calibration equipment.
Depending on the use, measurement environment, and internal quality control programs, we recommend recalibrating the microphone at least once a year.
Specifications
Typical frequency response (without protection grid). Upper curve shows free-field response for 0°, lower curve shows pressure response.
GRAS Sound & Vibration reserves the right to change specifications and accessories without notice.
Dimensions
