Examination of Umeå University's common lecture hall's sound environments and room acoustics : Focusing on speech intelligibility, reverberation time and installation noise

The purpose of this report was to investigate the sound environments in lecture halls at Umeå University and to assess to whether the sound environments in these lecture halls are satisfactory and whether have good speech intelligibility or not. Based on a web survey, a number of lecture halls were selected for this investigation, namely Hörsal A, Hörsal C, N280, KB.F3.01, Ma121, KB.E3.01, N340 and N335. Assessing room acoustics includes many relevant parameters, therefore a delimitation has been made. Only installation noise, reverberation time and speech intelligibility have been investigated. The methods followed established Swedish standards i.e SS-EN ISO 16032:2004 for installation noise,” integrated impulse response method” SS-EN ISO 3382:2:2008/AC:2009 for reverberation time and direct FULL STI (speech transmission index) IEC 60268-16:2011 for speech intelligibility. An ocular inspection was carried out of all the selected lecture halls. The result from the STI test showed that all the lecture halls except for Hörsal A have a good speech intelligibility, if the audience has normal hearing and they are listening to a lecture in their native language. In Hörsal A there are three measuring positions that fails to achieve the threshold for good speech intelligibility. The conclusion for all of the measurements that has been made are that Ma121 and KB.E3.01 has a satisfactory sound environment and that Hörsal A, Hörsal C, N280, KB.F3.01, N340 and N335 need actions to improve their sound environment so they can fulfil the benchmarks in Swedish public health authority regulations in FoHMFS 2014:13 and/or SS 25268:2007