Instrument for Soundscape Recognition, Identification and Evaluation

The parameters that are used to define a sound-field are necessarily governed by what is practical to measure. Predominantly sound is characterised by the A-weighted sound pressure level at a point and has remained so since the earliest sound level meters; partly as a result of this, most legislative controls and guidance are expressed in terms of A-weighted levels, often averaged over long periods of time (typically the hours of daytime and night-time). However, advances in technology mean that it may be possible for a sound meters to discriminate between and localise sound sources so it becomes possible to characterise a sound field in terms of the relative contribution of different sources. This is a significant departure from existing meters which are able to provide a detailed analysis of the characteristics of the sound at the measurement position but are not able to provide information directly on the source(s) contributing to sound at the measurement position. Such a meter could have a significant impact on planning guidance, for example, where it would be possible to consider both 'positive' sound sources (e.g. natural sounds such as a waterfall or birdsong) and 'negative' noise sources (e.g. highways, industrial processes). It would also be possible to identify potentially rare but loud sources (such as over-flying by military aircraft) which may make only a small contribution to averaged levels but which could be a source of great annoyance - currently this is only possible with attended monitoring (where the individuals remain with the sound meter) or by laborious analysis of audio recordings (which is not feasible in many instances).