title: [Effects of acaoustic adaptation of classrooms on the quality of verbal communication].
abstract: BACKGROUND
  Voice organ disorders among teachers are caused by excessive voice strain. One of the measures to reduce this strain is to decrease background noise when teaching. Increasing the acoustic absorption of the room is a technical measure for achieving this aim. The absorption level also improves speech intelligibility rated by the following parameters: room reverberation time and speech transmission index (STI). This article presents the effects of acoustic adaptation of classrooms on the quality of verbal communication, aimed at getting the speech intelligibility at the good or excellent level.
  
  
  METHODS
  The article lists the criteria for evaluating classrooms in terms of the quality of verbal communication. The parameters were defined, using the measurement methods according to PN-EN ISO 3382-2:2010 and PN-EN 60268-16:2011. Acoustic adaptations were completed in two classrooms.
  
  
  RESULTS
  After completing acoustic adaptations the reverberation time for the frequency of 1 kHz was reduced: in room no. 1 from 1.45 s to 0.44 s and in room no. 2 from 1.03 s to 0.37 s (maximum 0.65 s). At the same time, the speech transmission index increased: in room no. 1 from 0.55 (satisfactory speech intelligibility) to 0.75 (speech intelligibility close to excellent); in room no. 2 from 0.63 (good speech intelligibility) to 0.80 (excellent speech intelligibility). Therefore, it can be stated that prior to completing acoustic adaptations room no. 1 did not comply and room no. 2 barely complied with the criterion (speech transmission index of 0.62). After completing acoustic adaptations both rooms meet the requirements.
authors.affiliation: Centralny Instytut Ochrony Pracy - Państwowy Instytut Badawczy / Central Institute for Labor Protection - National Research Institute, Warszawa, Poland. wimik@ciop.pl
authors.forename: Witold
authors.initials: W
authors.lastname: Mikulski
mesh_terms: D000162:Acoustics; D003142:Communication; D005160:Facility Design and Construction / Q000379:methods*; D006801:Humans; D008962:Models, Theoretical; D009622:Noise; D009784:Occupational Diseases / Q000517:prevention & control; D012574:Schools; D013061:Speech Acoustics; D013065:Speech Intelligibility; D013663:Teaching; D014832:Voice Disorders / Q000517:prevention & control