Loudness criteria in auditorium acoustics

I.IntroductionLoudnessisoneofthedistinguishingcharactcristicsamonga1lacousticcriteriainauditori-umdesign.Insufficientorsevcrcunevendistributionofloudncsscausesseriousdeficiencytoauditoriumacoustics.Duetothelackofappropriateparamcter,thereisnowayeithertopre-dictloudnessinanauditoriumduringthedcsignstagc,ortochccktheactua1effectafterthecomp1etionoftheconstruction.Wca1lmighthavethcexpcricnccasanaudiencethatthestagcattractedmoreofourcon-ccntrationduringthesoftpassagcofthcpcrformance,whercaswewcre…

Loudness criteria in auditorium acoustics

Loudness, one of the distinguishing characteristics in auditorium acoustics, has received less attention by acoustical consultants than other parameters up to the present. Due to the lack of an appropriate paramcter, neither measurements in auditorium on this subject is practicable, nor prediction could be made during the design process. The frequently applied method is by means of the summation of the direct sound and the reverberant sound as the total sound level over the audience area. In fact, this is only suitable for predicting the sound level from a steady sound source and in the reverberant field, apparently not appropriate in practice either for acoustic design or for on-site measurement. Strength index G (Starkemass in Germany) (dB), proposed by Lehmann, as loudness criteria, might be a proper parameter. But,as the primary results from our investigation and from others as well, showed that the early reflections presented the main contribution to the perccived loudness, it is more reasonable to set a limit to the integrating time of index G, say 50 ms for speech and 80 ms for music, which have been commonly recognized as useful portion in "definition" and "clarity", instead of the infinitive integrating time as Lehmann proposed. Therefore, G50 and G80 are highly recommendedto be used as loudness criteria for speech and music in auditorium acoustics respectfully.