The core of the test system consists of a test unit Nor484 and a PC system featuring a 24-bit DAQ board and dedicated calibration software.

An indoor environmental monitor is delivered with the system, providing the required environmental data in a fast and accurate manner for the calibration reports.

A calibration of a sound level meter is normally divided into two main parts: electrical calibration of the sound measuring instrument and calibration of the microphone. Eventually, an accompanying sound calibrator may be calibrated and used for an overall system check.

The measured results are automatically logged and used for an automatic generation of a calibration certificate, with appropriate uncertainty statements. If needed, the certificate may be edited by the operator. Automatic generation of reported values minimize the risk for errors generated by the operator.

The calibration system Nor1525 may be configured to suit specified applications and consists typically of:

  • Personal computer.
  • Actuator chamber with reference microphone and insert voltage preamplifier.
  • Indoor environmental monitor.
  • Test unit Nor484 with microphone power supplies, amplifiers and filters.
  • Reference calibrator or pistonphone.
  • Support while setting up the system.

Periodic Verification of Sound Calibrators

  • Sound pressure level corrected for pressure, temperature and humidity.
  • Short term stability expressed in dB (option).
  • Output frequency in Hz.
  • Total distortion in % (option).

Periodic Verification of Sound Level Meters

The Periodic Verification of Sound Level Meters can be performed in accordance with several national and international standards. This includes measurements of:

  • Accuracy of input range selector.
  • Level linearity.
  • Spectral weighting networks A, B, C, Z, Lin and Flat.
  • F, S, and I time constants. Pulse measurement capability.
  • RMS detector capability.
  • Overload detector.
  • Inherent noise using microphone equivalent or acousti-cally insulated test vessel.
  • Integrating averaging functions Leq and SEL.
  • Noise dose.
  • 1/1 and 1/3 octave band filters (option).

The results from the microphone and instrument calibration may be combined to validate conformance with standards for a complete sound level meter.


The expanded uncertainties for calibrator and microphone measurements, are calculated as a combination of the uncertainty of the test system and the repeatability of the measurements. This includes the calculation of the standard deviations, degrees of freedom and coverage factor which are needed to estimate the 95% expanded uncertainty.
A digital and personalized course on uncertainties and how to set up an uncertainty budget can be purchased as option.


Each system is delivered with a certificate of calibration with traceability to SI units. Recalibration can be performed by the user with the built-in self test features (requires voltmeter), or by the manufacturer.



  • Frequency response calibration of microphones using the electrostatic actuator (with swept-sine) or acoustical method.
  • Sensitivity calibration of microphones using the insert voltage method ensures a high degree of accuracy.
  • Fast and accurate calibration of sound calibrators, pistonphones and associated barometers in accordance with IEC 60942 (2003 and 2017).
  • Sound level meter calibration in accordance with IEC 61672-3 (2006 and 2013), IEC 60651:1979, IEC 60804:2000, DIN 45657:2014, ANSI S1.4 (2014 and older), ANSI S1.43-1997 and BS 7580:1997.
  • Fast and accurate calibration of sound measuring instruments using three different interface modes; manual; semi-automated and fully automated.
  • Test of fractional octave filters in accordance with IEC 61260-3:2016.
  • 1260-3:2016. • Full test report generated.
  • Built-in self test features (requires voltmeter).
  • Easy to set up, includes all accessories needed.



Product range catalogue

  • Product range catalogue -

    Norsonic_productrange_2024-2025.pdf (0.01GB)
Product data

Nor1525 calibration system

  • Nor1525 calibration system -

    PD-Nor1525-Ed1Rev1_0424.pdf (790.76KB)


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