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Norsonic AS
Sound Calibrators

Sound Calibrators

Product catalog summary

Introduction
Sound calibrators are essential for accurate sound measurements. They serve both as verification tools and devices for adjusting the sensitivity of sound measuring instruments. The Norsonic range includes three models: Nor1251, Nor1252, and Nor1253, each differing in accuracy and application.

Specifications

Nor1251: Class 1 calibrator, 114 dB @ 1 kHz, suitable for full-inch and ½-inch cartridges with an adaptor.
Nor1252: Class 2 calibrator, 114 dB @ 1 kHz, designed for less critical applications, supports ½-inch and ¼-inch cartridges with an adaptor.
Nor1253: Class 0 calibrator, known as the "electronic pistonphone," offers high accuracy without barometric corrections, available in 124 dB SPL at 250 Hz or 1000 Hz.

Operating Principles
All calibrators operate on a common principle where a miniature loudspeaker generates sound pressure in a coupler. The sound pressure is measured by a silicon sensor, which adjusts the oscillator signal to maintain stability. This design minimizes sensitivity to ambient conditions such as temperature, humidity, and pressure.

Environmental Influence
The calibrators are designed to be minimally affected by ambient conditions. The Nor1253 and Nor1251 are calibrated across a temperature range of -10°C to +45°C to meet IEC and ANSI standards. The feedback system compensates for variations in microphone volume and loudspeaker drift.

Technical Data

Sound pressure level: Nor1253 - 124.0 ± 0.2 dB, Nor1251 - 114.0 ± 0.2 dB, Nor1252 - 114.0 ± 0.4 dB.
Frequency: Nor1253 - 250 Hz or 1000 Hz, Nor1251 and Nor1252 - 1000 Hz.
Distortion: <1% for all models.
Battery life: Nor1251 and Nor1252 - >30 hours, Nor1253 - >20 hours.

Conclusion
Norsonic sound calibrators are designed for precision and reliability, suitable for various applications depending on the required accuracy. They ensure stable sound measurements by compensating for environmental variations and maintaining consistent performance.

Catalog excerpts

Sound calibrators. No sound measurement is correct without them. The use of sound calibrators dates back to the days when it was easier to design a stable sound calibrator than a stable sound level meter. Today, sound measuring instruments, in general, are as stable as the sound calibrators. However, measuring microphones are very delicate devices designed to fulfill very rigid specifications. This makes them vulnerable and subject to damage unless care is taken. One may therefore say that a calibrator is just as much a verification of proper operation as it is a device for readjustment of sensitivity...

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Microphone to be checked Coupler Vented cavity cavity Pressure sensor (silicon microphone) Amplifier Bandpass filter Detector Oscillator Level controller LED Loudspeaker Nor1253 – the influence of ambient conditions All the sound calibrators have a very low sensitivity to the ambient pressure, humidity, temperature and the load volume. The Nor1253 and the Nor1251 are calibrated at three temperatures (–10 °C, +23 °C and 45 °C) to ensure that the output sound pressure level is well within the requirements set by the IEC 61 942 and ANSI S 1.40–1997 over the specified temperature range. The feedback...

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P.O.Box 24, N-3421 Lierskogen, Norway Tel.: +47 3285 8900 Fax: +47 3285 2208 [email protected] www.norsonic.com Distributor: Specifications Nor1253 Nor1251 Nor1252 IEC60942 (2003-01) Classification Class 1 1) Class 1 Class 2 Complies with ANSI S1.40 (1997) Yes Yes Yes Sound pressure level (re: 20ìPa) 124.0 ± 0.2 dB 114.0 ± 0.2 dB 114.0 ± 0.4 dB Frequency 250 Hz ± 0.2% 2) 1000 Hz ± 0.2% 1000 Hz ± 0.2% Distortion <1% <1% <1% Sensitivity to change in the load volume -0.00002 dB/mm3 (250Hz) +0.0003 dB/mm3 (1000Hz) +0.0003 dB/mm3 (1000Hz) +0.0003 dB/mm3 (1000Hz) Typical change in SPL per year < 0.01...

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Sound Calibrators

Sound Calibrators

Catalog excerpts

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