Measurement Uncertainty

Measurement uncertainty in room acoustics quantifies the range within which the true value of a measured parameter lies, accounting for spatial variation, equipment precision, and environmental factors. ISO 3382-2:2008 §6 provides guidance on uncertainty, recommending a minimum of 6 source-receiver combinations for adequate spatial sampling. Typical measurement uncertainties for RT60 in ordinary rooms are ±5% (one standard deviation) with proper spatial averaging. Factors contributing to uncertainty include source and receiver positions, background noise variations, temperature changes, and instrument calibration. The number of measurement positions, the room’s diffusion quality, and the frequency band all affect uncertainty. Low-frequency measurements (125 Hz) typically have higher uncertainty due to room modes. Reporting measurement uncertainty alongside results is considered best practice and is increasingly required by building regulations and certification schemes.