IEC 61094-4-1995 PDF

Full title and description

Measurement microphones - Part 4: Specifications for working standard microphones. This international standard specifies mechanical dimensions and defined electroacoustical characteristics for working standard microphones so they can be used as transfer standards in the calibration of acoustic measurement instruments and measurement systems.

Abstract

IEC 61094-4:1995 defines the physical and performance requirements for working standard (WS) measurement microphones, including type classification, declared sensitivities and uncertainties, environmental dependencies, effective front volume, dynamic range limits and linearity criteria. It is intended to ensure interchangeability of working standards within calibration and measurement systems and to support traceable transfer calibrations.

General information

• Status: Published / Valid (current edition as of publication; maintained in IEC bibliographic records).
• Publication date: 16 November 1995.
• Publisher: International Electrotechnical Commission (IEC).
• ICS / categories: 17.140.50 (Electroacoustics); 33.160.50 (Accessories).
• Edition / version: Edition 1.0 (1995).
• Number of pages: 23 pages (official IEC publication).

Scope

Applies to working standard microphones used in systems for the determination of sound pressure. The standard specifies nominal mechanical dimensions and tolerances, type classification (to facilitate interchangeability), reporting of open‑circuit sensitivity with stated uncertainties, effective front volume characteristics, upper limits of dynamic range (e.g., SPL at specified THD), linearity requirements over defined frequency ranges, and declared dependencies on static pressure, temperature and humidity. It does not prescribe the transduction principle.

Key topics and requirements

• Type classification system for working standard microphones (pressure, free‑field, diffuse‑field types and nominal dimensions).
• Nominal mechanical dimensions, mounting/connector/threading conventions and tolerances to ensure physical interchangeability.
• Required electroacoustical characteristics: open‑circuit sensitivity reporting (with resolution and uncertainty), effective front volume specification, frequency range requirements (typical reference band 160 Hz–1 000 Hz) and declared uncertainties.
• Dynamic range and distortion criteria (upper SPL limits for specified total harmonic distortion) and linearity limits within defined SPL ranges.
• Environmental dependency statements: sensitivity dependence on static pressure, temperature and humidity and the reference environmental conditions to be used for declared values.
• Use as transfer standards for calibration of measurement microphones and acoustic instruments (requirements that support traceability and low uncertainty transfer calibrations).

Typical use and users

Primary users are national and industrial calibration laboratories, acoustic and metrology laboratories, microphone and preamplifier manufacturers, test houses, and engineers performing instrument calibrations or intercomparisons. The standard is used when selecting, specifying or calibrating working standard microphones for routine transfer calibrations, field verifications and laboratory comparison measurements.

Related standards

IEC 61094 is a multi‑part series. Relevant related parts include IEC 61094‑1 (laboratory standard microphones), IEC 61094‑2 and IEC 61094‑3 (primary calibration methods by reciprocity for pressure and free‑field), IEC 61094‑5 (comparison methods for pressure calibration of working standards), IEC 61094‑6 (electrostatic actuators for frequency‑response determination) and later parts/technical specifications and guidance (for example IEC 61094‑8 and IEC/TS 61094‑7) that address calibration methods and free‑field/secondary techniques. National/adopted versions and related acoustics standards (e.g., IEC 60942 for sound calibrators) are commonly used together with IEC 61094‑4.

Keywords

Measurement microphones; working standard microphones; transfer standards; calibration; sensitivity; effective front volume; electroacoustics; microphone classification; dynamic range; environmental dependence.

FAQ

Q: What is this standard?

A: IEC 61094‑4:1995 is the international specification for working standard measurement microphones, defining mechanical and electroacoustical requirements so these microphones can be used reliably as transfer standards in calibration systems.

Q: What does it cover?

A: It covers classification, nominal dimensions and tolerances, reporting of open‑circuit sensitivity and uncertainty, effective front volume, limits on dynamic range and linearity, and the declaration of environmental dependencies (pressure, temperature, humidity) relevant to working standard microphones.

Q: Who typically uses it?

A: Calibration laboratories, acoustic test laboratories, microphone manufacturers, equipment calibration technicians and standards bodies use the standard to specify, compare and perform transfer calibrations of measurement microphones.

Q: Is it current or superseded?

A: IEC 61094‑4:1995 is the published edition from 16 November 1995. Users should check national and IEC catalogs for any amendments, revisions or later parts of the IEC 61094 series that affect calibration methods or practice; related parts of the series have been updated at later dates.

Q: Is it part of a series?

A: Yes — IEC 61094 is a multipart series covering measurement microphones and associated calibration methods (parts 1–8 and associated technical specifications). IEC 61094‑4 specifically addresses working standard microphones within that series.

Q: What are the key keywords?

A: Measurement microphones, working standard, transfer standard, calibration, sensitivity, effective front volume, electroacoustics, microphone classification, dynamic range, environmental dependence.