Nor1239 Free-field Microphone
Precision 1/4" free-field measurement microphone.
Overview
The Nor1239 is a precision 1/4" free-field prepolarized condenser measurement microphone designed for applications requiring extended high-frequency response and compact physical dimensions. With a usable frequency range extending from 4 Hz to 40 kHz, the Nor1239 significantly exceeds the bandwidth of standard 1/2" microphones, making it essential for ultrasonic measurements, aeroacoustic research…
Key Features
- Extended frequency range 4 Hz to 40 kHz for ultrasonic capability
- Prepolarized design requires no external polarization voltage
- 1/4" compact diameter minimizes acoustic interference
- Free-field optimized for directional measurements
- Wide dynamic range for versatile measurement applications
- Compatible with Nor1205 1/4" preamplifier
- Individual calibration certificate with traceable data
- Precision-manufactured for consistent high-frequency response
Applications
- Ultrasonic noise measurement and monitoring above 20 kHz
- Automotive NVH testing including brake squeal and tire noise
- Aeroacoustic research and wind tunnel measurements
- In-duct fan noise measurement in confined spaces
- Small cavity and coupler acoustic measurements
- Precision laboratory reference measurements
Technical Specifications
- Size: 1/4"
- Frequency: 4 Hz – 40 kHz
- Applications: Extended high frequency
Frequently Asked Questions
- Why would I need a 1/4" microphone?
The smaller 1/4" diameter provides accurate measurements at higher frequencies (up to 40 kHz) where the diffraction effects around a 1/2" microphone would cause significant errors. It also allows access to smaller measurement spaces and produces less acoustic interference near reflective surfaces. Choose a 1/4" microphone for ultrasonic measurements, aeroacoustic research, and confined-space applications. - What does prepolarized mean?
A prepolarized microphone has a permanent electrical charge built into the diaphragm during manufacture, eliminating the need for an external 200 V polarization voltage supply. This simplifies the measurement setup and makes the microphone compatible with a wider range of preamplifiers and measurement systems, while maintaining equivalent measurement accuracy. - Can the Nor1239 be used for standard audio-frequency measurements?
Yes, the Nor1239 covers the full audio range from 4 Hz to 40 kHz, so it can be used for standard measurements. However, the lower sensitivity compared to 1/2" microphones means it is best suited for applications where the extended high-frequency range is specifically needed. For routine audio-frequency measurements, a 1/2" microphone like the Nor1225 provides better signal-to-noise performance.
Application Guide
The Nor1239 Free-field Microphone belongs to the Norsonic Microphones range. See the Microphones application guide for system configuration, compatible accessories, and applicable measurement standards.
Related Norsonic Products
- Nor1205 1/4" Insert Voltage Preamplifier — Insert voltage preamplifier for 1/4" measurement microphones.…
- Nor1225 Free-field Microphone — Class 1 free-field measurement microphone.…
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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