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Blind estimation of reverberation time in classrooms and hospital wards

Kendrick, P, Shiers, N, Conetta, R, Cox, TJ, Shield, BM and Mydlarz, C 2012, 'Blind estimation of reverberation time in classrooms and hospital wards' , Applied Acoustics, 73 (8) , pp. 770-780.

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This paper investigates blind Reverberation Time (RT) estimation in occupied classrooms and hospital wards. Measurements are usually made while these spaces are unoccupied for logistical reasons. However, occupancy can have a significant impact on the rate of reverberant decay. Recent work has developed a Maximum Likelihood Estimation (MLE) method which utilises only passively recorded speech and music signals, this enables measurements to be made while the room is in use. In this paper the MLE method is applied to recordings made in classrooms during lessons. Classroom occupancy levels differ for each lesson, therefore a model is developed using blind estimates to predict the RT for any occupancy level to within ±0.07s for the mid-frequency octave bands. The model is also able to predict the effective room and per person absorption area. Ambient sound recordings were also carried out in a number of rooms in two hospitals for a week. Hospital measurements are more challenging as the occurrence of free reverberant decay is rarer than in schools and the acoustic conditions may be non-stationary. However, by gaining recordings over a period of a week, estimates can be gained within ±0.07 s. These estimates are representative of the times when the room contains the highest acoustic absorption. In other words when curtains are drawn, there are many visitors or perhaps a window may be open.

Item Type: Article
Themes: Built and Human Environment
Health and Wellbeing
Media, Digital Technology and the Creative Economy
Schools: Colleges and Schools > College of Science & Technology > School of Computing, Science and Engineering > Acoustics Research Centre
Journal or Publication Title: Applied Acoustics
Publisher: Elsevier
Refereed: Yes
ISSN: 0003-682X
Related URLs:
Funders: Funder not known
Depositing User: P Kendrick
Date Deposited: 12 Apr 2012 14:06
Last Modified: 20 Oct 2014 17:21

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