A review of methods for quantifying tonal and impulsive features in environmental noise

The UK Government’s Department of Trade and Industry, through its National Measurement System Directorate, has been funding a major research project on Environmental Noise. The aims were to improve the quality and face validity of environmental noise measurements, and to contribute to the improvement of British, and International Standards on environmental noise. The project had three related aspects, with a separate work package being organized for each aspect: • A critical review and inter-comparison of methods of quantifying acoustic features in environmental noise, such as tones and impulses – Work Package 1. • Identifying and quantifying sources of uncertainty in environmental noise measurements. – Work Package 2. • Publishing practical guidance on minimizing such uncertainties Work Package 3. The authors are part of the consortium of consultants undertaking the project and have been responsible for the first work package, on acoustic features. In a paper at Internoise 2004 in Prague [1], we outlined the background to the project, explained the approach and methods used in the review and summarized the status of the project. Progress in Work Packages 2 and 3 was reported in another paper at Internoise 2004 [2]. In the present paper we describe the later phases of our specific part of the project, including; • a detailed review, and synthesis of a large number of previous research publications in which intercomparisons of the ‘performance’ of methods of quantifying acoustic features have been documented • a survey of the state of the art on practical implementations of various methods, in commercial instrumentation, and in systems used in research, • some new small-scale intercomparisons involving a selected number of methods. • our overall conclusions and recommendations.