The 41AC-3 is a small precision outdoor microphone according to IEC 61672-1 for monitoring of community noise and the noise of overhead aircraft.
Typical Applications and Use
With state of the art weather protection and extensive use of high-grade stainless steel, the 41AC-3 is ideal for long-term unattended monitoring of community noise and noise from overhead aircraft.
It can easily be configured for measurement of noise with 90 degrees of incidence, typically community noise, or – with the proper correction data – for measurement of noise with 0 degrees of incidence, typically overhead aircraft. A USB flash drive with the necessary 1/12 octave correction data is part of the delivery.
The 41AC-3 has been designed to meet the need for a precise and reliable outdoor microphone that can be part of a permanent installation. It is weather proof, easy to configure and calibrate.
It uses a 40AE-S2 1/2” Prepolarized Free-Field Microphone, High Sensitivity and a 26CA 1/2’’ CCP Preamplifier with BNC Connector.
Microphone and preamplifier are mounted inside a high-grade stainless steel housing. The top cone – also made of stainless steel – has been perfected for best acoustical response with the 40AE-S2 microphone. In addition to its acoustical function, the top cone acts as a bird spike.
The 40AE-S2 microphone has been modified for optimal response with respect to the sound field and the top cone’s internal cavity. The protection grid is a special design that offers added water protection.
The wind screen eliminates the effects of air flow and also serves as part of the 41AC-3’s water protection. It is glued to a detachable tube that ensures correct positioning. A locking system eliminates the risk of accidental dislocation. The 41AC-3 is waterproof and fulfils the requirements of IP-55. It is designed to withstand a wide range of weather conditions and temperatures for a very long period, i.e. easily a year or longer.
It comes with an adapter for pipe mounting. An adapter for tripod mounting is also part of the delivery.
It has TEDS accoording to IEEE1451.4 template UDID 127-0-0-0U.
The 41AC-3 uses a prepolarized microphone and a standard CCP preamplifier that requires a BNC to BNC cable and an input module compatible with this technology.
For verification of the microphone's sensitivity, we recommend using a pistonphone like the G.RA.S. 42AP Intelligent Pistonphone.
Before leaving the factory, all G.R.A.S. products are calibrated in a controlled laboratory environment using traceable calibration equipment.
An individual test certificate stating the sensitivity and frequency response is included with each product.
Performance and Warranty
G.R.A.S. outdoor microphones are made of components from our proven standard portfolio and are all manufactured of high-quality material and branded parts that were chosen and processed to ensure life-long stability and robustness.
All parts are manufactured and assembled at the factory in Denmark by skilled and dedicated operators in a verified clean-room environment. The microphone diaphragm, body and unique protection grid are made of high-grade stainless steel and make the microphone set resistant to physical damage as well as corrosion caused by aggressive air or gasses.
This, together with the enforced gold-plated microphone terminal which guarantees a highly reliable connection, enables us to offer 5 years warranty against defective materials and workmanship. The windscreen comes with a 6-month warranty.
The warranty does not cover products that are damaged due to negligent use, an incorrect power supply, or an incorrect connection to the equipment.
Service and Repairs
All repairs are made at G.R.A.S. International Support Center located in Denmark. Our Support Center is equipped with the newest test equipment and staffed with dedicated and highly skilled engineers. Upon request, we make cost estimates based on fixed repair categories.
If a product covered by warranty is sent for service, it is repaired free of charge, unless the damage is the result of negligent use or other violations of the warranty. All repairs are delivered with a service report, as well as an updated calibration chart.
|Frequency range (±1 dB)||Hz||5 to 10 k|
|Frequency range (±2 dB)||Hz||3.15 to 20 k|
|Dynamic range lower limit (microphone thermal noise)||dB(A)||17|
|Dynamic range upper limit||dB||138|
|Set sensitivity @ 250 Hz (±3 dB)||mV/Pa||50|
|Power supply (Constant Current Power)||mA||2 - 20 mA|
|Temperature range, operation||°C / °F||-30 to 70 / -22 to 158|
|Temperature range, storage||°C / °F||-40 to 85 / -40 to 185|
|Temperature coefficient @250 Hz||dB/°C / dB/°F||-0.01 / -0.006|
|Static pressure coefficient @250 Hz||dB/kPa||-0.014|
|Humidity range non condensing||% RH||0 to 95|
|Influence of axial vibration @1 m/s²||dB re 20 µPa||62|
|TEDS UTID (IEEE 1451.4)||27 v. 1.0|
|CE/RoHS compliant/WEEE registered||Yes/Yes/Yes|
1/2” Prepolarized Free-field Microphone, High Sensitivity
USB flash drive containing correction data (resolution: 1/12 octave)
1” Pole Mount Adapter
Tripod Thread Adapter
3 m BNC - BNC Cable
10 m BNC - BNC Cable
30 m BNC - BNC Cable
Customized length BNC - BNC Cable, xxxx length in cm.
1-Channel Power Module
Intelligent Pistonphone, Class 0