IEC 60942:2017

Overview

IEC 60942:2017 - Electroacoustics - Sound calibrators defines performance, test and documentation requirements for portable and laboratory sound calibrators used to generate a known sound pressure level for calibrating microphones and sound level meters. The fourth edition specifies three main classes of sound calibrator - class LS (Laboratory Standard), class 1, and class 2 - and sets acceptance limits, test procedures and measurement uncertainty criteria for demonstrating conformance. The standard also introduces pistonphone-specific designations (LS/M and 1/M) and updated conformity assessment rules.

Keywords: IEC 60942:2017, sound calibrators, electroacoustics, class LS, class 1, class 2, pistonphone, calibration

Key topics and requirements

• Classes and intended use:
  • Class LS - laboratory reference with the tightest acceptance limits (used with laboratory standard microphones).
  • Class 1 - for use with class 1 sound level meters (field or lab).
  • Class 2 - for use primarily with class 2 sound level meters (field use).
• Microphone specifications: Requirements reference IEC 61094 series - IEC 61094-1 (laboratory standard microphones) and IEC 61094-4 (working standard microphones).
• Performance metrics: Generated sound pressure level, short-term level fluctuation (level stability), frequency accuracy, total distortion + noise, and behavior over supply voltage and environmental ranges.
• Conformance assessment: Demonstrated when measured deviations do not exceed acceptance limits and measurement uncertainty is within maximum-permitted values (expanded uncertainty, 95% coverage).
• Environmental and EMC tests: Influence of static pressure, temperature and humidity; changes to avoid icing; immunity to radio-frequency fields including an alternative TEM-waveguide test; electrostatic discharge and emissions testing.
• Pattern evaluation and periodic tests: Normative annexes detail submission, test methods, reporting and periodic re-calibration procedures.
• Marking and documentation: Required labels, instruction manuals and calibration charts for class LS units.

Practical applications and users

IEC 60942:2017 is essential for:

• Calibration laboratories and ISO/ILAC-accredited labs performing microphone and sound level meter calibration.
• Manufacturers of sound calibrators and pistonphones implementing design verification and pattern approval.
• Environmental and occupational noise monitoring services ensuring traceable, compliant field calibrations.
• Acoustic test engineers and quality managers responsible for equipment conformity and maintenance.

Keywords: sound calibrator calibration, pistonphone, acoustic calibration, measurement uncertainty, IEC standards

Related standards

• IEC 61672-1 - Sound level meters (relationship of calibrator class to meter class)
• IEC 61094-1 - Laboratory standard microphones
• IEC 61094-4 - Working standard microphones

IEC 60942:2017 provides the technical baseline for reliable, traceable calibration of acoustic measurement chains and is a key reference for manufacturers, test labs and acoustic professionals.