On the applicability of models for outdoor sound

Karsten B. Rasmussen
1999 Journal of the Acoustical Society of America  
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more » ... Also, the following poster sessions are scheduled: Poster Session 2pSCb Poster Session 2pSPb TUESDAY AFTERNOON, 16 MARCH 1999 ROOM H105, 1:55 TO 4:00 P.M. Measurements of spatial room acoustical impulse responses were performed to provide a database for the examination of speech intelligibility ͑SI͒ in real rooms. As is well known, the spatial distribution of reflections can influence the SI, especially in reverberant rooms. Nevertheless, the qualitative and quantitative dependences are mostly unknown. Room acoustical measurements thus were realized using a dodecahedron loud-speaker for measuring reverberation time, an interference-free loudspeaker with omnidirectional characteristic for recording impulse responses, and an artificial speaker and a dummy head microphone for measurements of SI criteria and recording of logatom syllables. A specially constructed spaced four-capsule microphone in tetrahedron arrangement was used for measuring also. The four-microphone analysis technique can recognize intensity and direction of the early reflections ͓Odjija and Krämer ͑1999͔͒. Results of the measurements will be documented and published on a CD-ROM, together with the architectural data of the auditoriums. First results of the room acoustical measurements are presented. Prior studies have shown that reproducing the measured binaural cues with headphones does 1044 1044 not influence the SI significntly. Subjective measurements of SI and analysis of spatial dependences will be performed in a second stage of the project. 2pAAa8. Simulated acoustic field in mudejar-gothic churches. Miguel Galindo, Teofilo Zamarreno, Sara Giron ͑Dept. Fisica Aplicada, Universidad de Sevilla, Spain, teofilo@cica.es͒, Juan J. Sendra, and Jaime Navarro ͑Dept. Construcciones Arquitectonicas, Universidad de Sevilla, Spain͒ The most significant acoustic parameters in a set of mudejar-gothic churches were measured ͑all the churches were located in the city of Seville͒. From the analysis of these data important conclusions were otained about the behavior of the reverberant field versus source-receiver distance ͓J. Sendra et al., Computational Acoustics and its Environmental Applications-II ͑Computation on Mechanics Publications, Southampton, 1997͒, pp. 139-148͔ from Barron's revised theory ͓Barron et al., J. Acoust. Soc. Am. 84, 618-628 ͑1988͔͒ and the relations between several acoustics quality descriptors: C80, D50, and RASTI ͓Zamarreno et al., Proceedings Acustica-98, Lisbon ͑1998͔͒. The three most representative churches were chosen to carry out a computer simulation with the RAYNOISE software. Absorption coefficient values used in the model have been adjusted using measured reverberation time data, and thus the results were obtained for the other acoustic parameters in the different octave bands. It was proven that, in general, simulated values are coherent with the experimental results. Moreover, according to other authors ͓L. Marshall, J. Acoust. Soc. Am. 94, 2251-2261 ͑1994͔͒, it has also been proven that C80 and D50 indices need no spectral analysis and their broadband values and their averages in significant bands ͑500-2000 Hz͒ are indifferent. TUESDAY AFTERNOON, 16 MARCH 1999 ROOM H105, 4:15 TO 6:20 P.M.
doi:10.1121/1.425063 fatcat:rx6rqlhfqras5gqdrobu6sl4vi