The relation between spatial impression and the law of the first wavefront

In the field of room acoustics, it is popular belief that the early and late reflections contribute to auditory source width (ASW) and listener envelopment (LEV), respectively. However, some papers have demonstrated results not necessarily in agreement with the belief. In this paper, a hypothesis is proposed to clarify the essentials of ASW and LEV from point of view of the auditory phenomenon. The hypothesis is that the components of reflections under and beyond the upper limit of validity for the law of the first wavefront contribute to ASW and LEV, respectively. Two experiments were performed to evaluate the hypothesis. In the first experiment, the results showed directly that the components of reflections under the upper limit of validity for the law contribute to ASW. In the second experiment, four kinds of threshold were measured to evaluate the relation between the effect and LEV: image-splitting which corresponds to the upper limit of validity for the law, LEV, reverberation perception, and reverberation disturbance. The results showed that the threshold of image-splitting coincides with the that of LEV. This suggests that the components of reflections beyond the upper limit of validity for the law contribute to LEV. In conclusion, it seems that the results of experiments shown in this paper favor the hypothesis.

[1]  J. Blauert.  Spatial Hearing: The Psychophysics of Human Sound Localization , 1983 .

[2]  Hiroshi Furuya,et al.  Arrival direction of late sound and listener envelopment , 2001 .

[3]  Kazuhiro Iida,et al.  The role of reflections from behind the listener in spatial impression , 2001 .

[4]  A. H. Marshall,et al.  Spatial impression due to early lateral reflections in concert halls: The derivation of a physical measure , 1981 .

[5]  Scott G. Norcross,et al.  Objective Measures of Listener Envelopment in Multichannel Surround Systems , 2003 .

[6]  L. Thurstone.  A law of comparative judgment. , 1994 .

[7]  Dana S. Hougland,et al.  Concert and Opera Halls: How They Sound , 1996 .

[8]  Arup Acoustics,et al.  Book Review: Auditorium Acoustics and Architectural Design , 1994 .

[9]  J S Bradley,et al.  On the combined effects of early- and late-arriving sound on spatial impression in concert halls. , 2000, The Journal of the Acoustical Society of America.

[10]  K Kurozumi,et al.  The relationship between the cross-correlation coefficient of two-channel acoustic signals and sound image quality. , 1983, The Journal of the Acoustical Society of America.

[11]  Hiroshi Furuya,et al.  Effect of early reflections from upside on auditory envelopment , 1995 .

[12]  L. Cremer,et al.  Die wissenschaftlichen Grundlagen der Raumakustik , 1976 .

[13]  L. Thurstone,et al.  A low of comparative judgement , 1927 .

[14]  M. Morimoto,et al.  The relation between auditory source width and the law of the first wave front , 1992 .

[15]  M. Morimoto,et al.  Effects of low frequency components on auditory spaciousness , 1988 .

[16]  Michael Barron,et al.  Auditorium Acoustics and Architectural Design , 1993 .

[17]  M. Barron.  The subjective effects of first reflections in concert halls—The need for lateral reflections , 1971 .

[18]  G. A. Soulodre,et al.  Objective measures of listener envelopment , 1995 .

[19]  John S. Bradley,et al.  The influence of late arriving energy on spatial impression , 1995 .

[20]  Kazuhiro Iida,et al.  A chart of %-split of sound image , 1990 .

[21]  K. Iida,et al.  A new physical measure for psychological evaluation of a sound field: Front/back energy ratio as a measure for envelopment , 1993 .

[22]  Toshiki Hanyu,et al.  A NEW OBJECTIVE MEASURE FOR EVALUATION OF LISTENER ENVELOPMENT FOCUSING ON THE SPATIAL BALANCE OF REFLECTIONS , 1999 .