OM241/OM261 Semi-permanent Outdoor Microphone Class 1

OM241/OM261 semi-permanent outdoor microphone is developed by BSWA Tech for outdoor noise monitor. Semi-permanent outdoor microphone has no built-in calibration device and therefore requires periodic calibration using a sound calibrator for short-term noise measurement.

The frequency response of OM241 is optimized for 0° incidence, primarily for aircraft and airport noise measurement. The OM261 is optimized for 90° incidence, primarily for urban, traffic and industrial noise measurement. Both of two types of microphones have been specially designed to achieve the free-field frequency response in specified direction of incidence within the limits of IEC 61672-1. Each microphone is supplied with an individual calibration certificate that contains the actual sensitivity and free-field frequency response data for the complete set of outdoor microphones. Users can use the calibration data to correct the measurement data for more accurate results.

OM241/OM261 meets the IP54 ingress protection rating. The 90mm windscreen, internal rain hood and dust mesh can fully protect microphone to against wind, rain, snow, dust and other severe weathers. The bird spike prevents impact of perching birds to the measurement.

Technical Parameters
Type OM241 | OM261
Application Aircraft and airport noise | Urban, traffic and industrial noise
Incidence 0° | 90°
Standard GB/T 3785.1-2010 1级, IEC 61672-1:2013 Class 1, ANSI S1.4-1983 Type 1
Built-in Microphone 1/2” prepolarized measurement microphone
Sound Field Free-field
Open-circuit Sensitivity 50mV/Pa
Frequency Response 10Hz~20kHz (According to IEC 61672-1)
Dynamic Range 17dBA~134dBA(50mV/Pa)
Peak SPL 137dBA peak
Maximum Output Voltage 5Vrms
Inherent Noise 17dBA
Output Impedance <30ohm
Power Supply ICCP power supply (2mA~20mA, 4mA Typ.)
Conditions Temperature: -30℃~80℃, Humidity: 0%~95%RH
Connector BNC
Mounting Thread 1/4” thread
Enclosure IP54 (Microphone vertical placement only)
Size(mm) 90x222 (without extension rod), 90x372 (with extension rod)
Weight 89g (without extension rod), 203g (with extension rod)

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