Overview
EN 61094-5:2016 - Electroacoustics: Measurement microphones - Part 5 - specifies methods for pressure calibration of working standard microphones by comparison. It applies to working standard microphones (with removable protection grids) that meet EN 61094-4 and to laboratory standard microphones that meet EN 61094-1. The standard describes comparison techniques using either a laboratory standard microphone calibrated per EN 61094-2 or another working standard calibrated according to this part. It defines reference environmental conditions (23.0 °C, 101.325 kPa, 50% RH) and gives practical guidance, examples of couplers and jigs, and uncertainty analysis.
Key Topics
- Principle of comparison: The ratio of pressure sensitivities equals the ratio of open‑circuit output voltages when reference and test microphones are exposed to the same sound pressure (simultaneously or sequentially). Sensitivity (magnitude and phase) of the test microphone is derived from the known reference.
- Calibration methods: Procedures for simultaneous excitation (microphones exposed together using couplers or jigs) and sequential excitation (one microphone at a time in a coupler).
- Factors affecting pressure sensitivity:
- microphone pressure equalization mechanism
- polarizing voltage and driven‑shield configuration
- reference shield configuration and pressure distribution over diaphragms
- environmental dependence (temperature, humidity, barometric pressure)
- microphone capacitance, acoustic impedance and separation distance
- Uncertainty and validation: Identification and treatment of uncertainty components (reference sensitivity, measurement noise, pressure differences between microphones, acoustic coupling, etc.), and validation procedures.
- Informative annexes: Practical examples of couplers and jigs (e.g., couplers for WS2 up to 10 kHz, jigs for WS2/WS3 to higher frequencies), methods for open‑circuit sensitivity determination, and a typical uncertainty budget.
Applications
- Calibration laboratories and national metrology institutes performing pressure calibration of measurement microphones.
- Microphone manufacturers and acoustic test facilities ensuring traceable sensitivity measurements for working standard microphones.
- Acoustic consultants and quality‑assurance teams needing reliable microphone calibration methods for sound level measurements, environmental noise monitoring, and product testing.
- Useful where multi‑frequency, broadband, or rapid comparative calibrations are required, including calibration of microphones installed with specific preamplifiers.
Related Standards
- EN 61094-1 - Measurement microphones: specifications for laboratory standard microphones
- EN 61094-2 - Laboratory microphone calibration methods (harmonized reference)
- EN 61094-4 - Specifications for working standard microphones
EN 61094-5:2016 is essential for anyone managing microphone calibration programs, ensuring consistent, traceable pressure‑sensitivity measurements and well‑characterized calibration uncertainty.