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Calibrators

Nor1256

Class 1 Sound calibrator

Nor1256 is a compact, battery-powered, precision class 1 microphone calibrator designed in accordance with IEC 60942 and ANSI S1.40. Each unit is delivered with an individual accredited calibration certificate, ensuring full traceability for compliance documentation.

With two selectable sound pressure levels and two frequencies, Nor1256 enables straightforward verification of both level linearity and frequency linearity of your measurement chain. In addition, the calibrator continuously monitors ambient air pressure, temperature, and humidity, so you can document environmental conditions and maintain reliable, standards-compliant results.

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How to calibrate a microphone

This short video demonstrates how to calibrate a microphone on a Nor150 sound level meter using Nor1256, a class 1 sound calibrator.

Quartz-controlled digital design for stable calibration

The all-digital design is built around a quartz-controlled signal generator that delivers a highly stable output signal, ensuring exceptional frequency stability for reliable sound calibration. A precision reference microphone and control circuit maintain a constant sound pressure level in the calibration coupler and automatically compensate for changes in load volume, temperature, humidity, and barometric pressure. The selected level and frequency are clearly shown on the high-contrast OLED display, and each unit is supplied with an individual accredited calibration certificate for documented traceability.

Dual levels and frequencies for versatile microphone verification

Nor1256 establishes a higher performance level for professional sound calibrators by combining two calibration levels and two frequencies with simultaneous measurement of ambient temperature, relative humidity, and static pressure. It generates sound pressure levels of 94 dB and 114 dB (re. 20 µPa) at 250 Hz and 1000 Hz. This combination of levels and frequencies supports both linearity and frequency response verification of microphones, enabling a wide range of calibration tasks to be completed with a single instrument.

Clear OLED display and intuitive user operation

All key parameters – calibration level, frequency, and environmental conditions – are presented on the OLED display for immediate visual verification. The calibrator fits directly onto 1" microphones and can be used with smaller microphone sizes via adapters, supporting flexible use across different measurement setups. On power-up, the instrument generates 114 dB at 1000 Hz. A press of the dB button toggles between 94 dB and 114 dB, while the Hz button switches between 1000 Hz and 250 Hz. The °C/°F button displays the current ambient pressure, temperature, and humidity, helping users document and repeat calibration conditions accurately.

Features

Standards

Specifications

Downloads

Features

Conforms to EN/IEC 60942:2017 Class 1, and ANSI S1.40–2006.
Ultra-stabile silicone reference microphone.
Fully compensated for static pressure, humidity, and temperature.
Sound pressure independent of microphone equivalent volume.
Robust, compact and battery operated.
114 and 94dB @ 1000 and 250 Hz.
Built in display.
Measurement of humidity, temperature and static pressure.
Delivered with individual accredited calibration certificate

Standards

EN/IEC 60942:2017
ANSI S1.40–2006

Specifications

General Sound calibrator class 1 according to:

EN/IEC 60942 : 2017 Class 1
ANSI/ASA S1.40-2006 (R2011).

Microphone size: 1/1” and below.
Calibrator frequency (@ Reference conditions): 251.19±0.30 Hz and 1000 ±1.00 Hz
Generated Sound Pressure Level relative to 20μPa (@ Reference conditions): 114.0±0.2 dB and 94.0±0.2 dB
Distortion: Max 2.0%
Stabilizing time: 20 seconds
Sensitivity to environmental conditions: As specified for IEC 60942 class 1 / ANSI S1.40.

Environmental range for specified operation:
Temperature: -10ºC to +50ºC / 14ºF to 122ºF
Relative humidity: 25% to 90%
Air pressure: 65 kPa to 108 kPa

Display type and resolution: Mono-colour OLED graphical display – 128×64 (WxH)

Additional specifications for the built in ambinet measurement sensors:
Temperature range: -10ºC to +50ºC or 14ºF to 122ºF
Resolution / Accuracy: 0.1ºC / ±2ºC or 0.1ºF / ±2ºF
Atmospheric pressure: 65 kPa to 108 kPa; Resolution 0.1kPa; Accuracy ±0.4 kPa, (for temperature above 0ºC)
Relative humidity: 0% to 100%; Resolution 1%; Accuracy ±4%, (for temperature above 0ºC and humidity in the range 25% to 85%)

Power off: By power switch or when microphone is removed (may be deactivated)

Battery type: 2 x LR03 alkaline batteries (AAA-size)
Battery life: > 10 hours
Battery low: Automatically switching off if battery voltage too low

Weight: 125 g / 0.28 lb
Dimensions: ( LxWxH ): 97×51.5×41 mm / 3.8×2.0×1.6 “

Accessories included:
(may vary if supplied as part of a Sound level meter kit):