Description
The Environmental Microphone System Type 41AL is designed for outdoor acoustic measurements, capable of withstanding continuous rain and operating over a wide temperature range. It is suitable for short-term noise monitoring, offering a cost-effective alternative to permanent systems like Types 41AM and 41CN.

Specifications
The microphone complies with IEC 651 Type 1 and ANSI S1.4 1983 Type 1 standards. It features a ½″ condenser microphone with a foam windscreen, anti-bird spikes, and a rain protection cap. The system operates with a power supply range of 28 V to 120 V and has a polarization voltage of 200 V for externally polarized versions. The operating temperature range is -40 °C to +60 °C.

Typical Applications

• Outdoor noise measurements
• Traffic noise monitoring
• IEC 60651 Sound Level Meter measurements
• Environmental surveillance

Versions
There are four versions of the Type 41AL microphone, each optimized for specific applications:

• Type 41AL-S: Community noise, 90º incidence, externally polarized
• Type 41AL-1: Airport noise, 0º incidence, externally polarized
• Type 41AL-2: Community noise, 90º incidence, prepolarized
• Type 41AL-6: Airport noise, 0º incidence, prepolarized

All versions can include SysCheck for performance verification.

Performance
The microphone has a sensitivity of 50 mV/Pa and a frequency response that meets stringent IEC and ANSI standards. It has a dynamic range upper limit of >156 dB and a total system noise level of <17 dB A-weighted.

Accessories
Included accessories are a complete windscreen, tripod adapter, and a 3-meter LEMO cable. Optional accessories include a pistonphone adapter, desiccator unit, foam windscreens, pole adapter, and a 10-meter extension cable.

Installation and Use
For optimal protection, the microphone's diaphragm should remain horizontal. The 0º version is ideal for aircraft noise measurements, while the 90º version is suited for community and traffic noise. A desiccator unit is recommended for extended outdoor use to prevent moisture ingress.