IEC 60268-4:2018

Overview

IEC 60268-4:2018 - Sound system equipment - Part 4: Microphones - is the international measurement standard that defines how to characterize and specify sound‑system microphones for speech and music. This 2018 (Edition 6.0) technical revision replaces the 2014 edition and specifies measurement methods and the set of microphone characteristics manufacturers should provide. It applies to each audio channel of multi‑channel microphones, flush‑mounted microphones and the analogue characteristics of microphones with digital outputs. Measurement microphones are explicitly excluded.

Key topics and technical requirements

The standard prescribes methods of measurement and the characteristics to be specified, covering major subjects (Clauses 6–21) and additional items in annexes:

• Electrical impedance - internal and rated impedance and methods of measurement
• Sensitivity - free‑field, diffuse‑field, near‑field/close‑talking and pressure sensitivities; rated sensitivity reporting
• Frequency response and effective frequency range - point‑by‑point and continuous sweep methods, calibration and graphical presentation
• Directional characteristics - polar/directional response patterns and directivity index measurements
• Dynamic range and non‑linearity - total harmonic distortion, harmonic orders and difference‑frequency distortion
• Limiting characteristics - rated maximum permissible peak sound pressure and overload conditions
• Noise - equivalent sound pressure due to inherent noise (Annex D adds noise measurements in the digital domain)
• External influences - mechanical vibration, wind noise, and transient “pop” effects (subclause 19.4 replaces previous Annex C)
• EMC and immunity - electromagnetic compatibility, immunity criteria and testing for preserving programme quality
• Environmental and physical conditions - ambient pressure, temperature, humidity ranges, connectors, reference point/axis, and pre‑conditioning requirements

The standard also defines measurement environments (free‑field, diffuse field, small cavity couplers), calibration approaches, and reporting/graphical presentation rules.

Practical applications and who uses it

IEC 60268-4:2018 is used by:

• Microphone manufacturers for R&D, product specification, datasheets and compliance testing
• Acoustic and audio test laboratories to produce reproducible, comparable measurements
• System integrators, broadcasters and live‑sound engineers to select microphones for speech or music applications
• Procurement and quality assurance teams to verify performance claims and acceptance testing

Practical uses include component selection, design verification, product comparison, certification and ensuring reliable operation under real‑world environmental and EMC conditions.

Related standards

• Part of the broader IEC 60268 series (sound system equipment); consult other parts of the series for loudspeaker, amplifiers and system‑level test methods.