Nor1225 Free-field Microphone
Class 1 free-field measurement microphone.
Overview
The Nor1225 is a precision 1/2" free-field condenser measurement microphone designed to meet the demanding requirements of IEC 61094-4 Class 1. With a nominal sensitivity of 50 mV/Pa and a wide frequency response from 3.15 Hz to 20 kHz, the Nor1225 is the standard microphone supplied with Norsonic sound level meters for general-purpose environmental, occupational, and building acoustics measuremen…
Key Features
- IEC 61094-4 Class 1 precision free-field microphone
- Nominal sensitivity 50 mV/Pa for excellent signal-to-noise ratio
- Wide frequency range 3.15 Hz to 20 kHz covering full audio band
- TEDS (IEEE 1451.4) compatible for automatic configuration
- 200 V externally polarized for maximum measurement stability
- Standard 1/2" diameter fits all Norsonic preamplifiers
- Free-field optimized for directional noise measurements
- Individual calibration chart with traceable sensitivity data
Applications
- Environmental noise monitoring per ISO 1996 and IEC 61672
- Occupational noise assessment per ISO 9612
- Building acoustics testing per ISO 16283 and ISO 3382
- Construction site noise compliance monitoring
- Airport and transportation noise measurements
- Industrial noise source identification and assessment
Technical Specifications
- Standards: IEC 61094-4 Class 1
- Size: 1/2"
- Frequency: 3.15 Hz – 20 kHz
- Sensitivity: 50 mV/Pa nominal
Frequently Asked Questions
- What is free-field response?
A free-field microphone is designed to measure sound arriving from a specific direction (typically 0° incidence), with its frequency response corrected for the diffraction effects caused by the microphone body in the sound field. This provides accurate readings of the undisturbed sound pressure that would exist at the measurement point without the microphone present. - When should I use a different microphone type?
Use a diffuse-field (random-incidence) microphone when measuring in reverberant environments where sound arrives from all directions equally, such as reverberation time measurements. Use a pressure-field microphone for cavity or coupler measurements where the microphone diaphragm forms part of the cavity wall, such as calibration couplers or ear simulators. - Is the Nor1225 suitable for outdoor measurements in Gulf climates?
Yes, the Nor1225 is designed for operation in temperatures up to +50°C, making it suitable for the extreme heat encountered across the GCC. When used with an appropriate outdoor microphone kit (such as Nor1216), it provides reliable Class 1 accuracy for permanent outdoor monitoring in high-temperature, high-humidity, and dusty conditions.
Application Guide
The Nor1225 Free-field Microphone belongs to the Norsonic Microphones range. See the Microphones application guide for system configuration, compatible accessories, and applicable measurement standards.
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Why Norsonic?
- Manufactured in Norway — decades of acoustic measurement heritage; all instruments designed and built in Norsonic AS, Lierskogen, Norway
- IEC 61672 Class 1 — highest accuracy class for professional and regulatory acoustic measurement
- International type approvals — PTB (Germany) and LNE (France); accepted by environmental authorities across the region
- 3-year manufacturer warranty — covers parts and labour; Norsonic Asia authorized service center support throughout the region
- Open data formats — .nox files work with NorReview and can be exported to CSV, Excel, and third-party analysis software
Calibration and Compliance
- All Norsonic instruments require periodic IEC 61672-3 calibration — Norsonic Asia provides factory-authorized calibration services with full DANAK-traceable certificates
- Calibration interval: 1 year for ISO 17025 accredited laboratories; 2 years for field instruments in non-accredited applications
- Field calibration check: use an IEC 60942 Class 1 sound calibrator (94 dB or 114 dB) before and after each measurement session
- Loaner instruments available during calibration to minimize project downtime — contact Norsonic Asia for loaner availability
Availability & Regional Support
Available from Norsonic Asia — the factory-authorized distributor for ASEAN, GCC, and South Asia. Instrument supply includes 3-year manufacturer warranty, factory-authorized calibration services, operator training, and after-sales technical support.
- Typical lead time: 3–6 weeks from order confirmation (ex-factory Norway)
- Countries served: Singapore, Malaysia, Thailand, Vietnam, Philippines, Indonesia, UAE, Saudi Arabia, Qatar, Kuwait, India, Bangladesh, Sri Lanka, and more
- Technical support: English and Arabic; response within 1 business day
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