The Use of Virtual Reflectors to Improve Speech Intelligibility in Open Stage Auditoria

Abstract

A potential problem encountered with open stage auditoria is poor speech intelligibility arising from the directional nature of human speech sources. The conventional technique of employing large overhead reflecting surfaces to ensure a large early energy fraction to improve intelligibility is shown to be unsuitable in this situation. The use of Virtual Reflectors consisting of microphones and loudspeakers symmetrically located relative to the stage is proposed as a possible solution to the problems of open stage auditoria. It is suggested that the Speech Transmission Index is a suitable parameter for assessing the performance of Virtual Reflectors when in use and that computer modelling could provide a suitable method for investigating the action of Virtual Reflectors.

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References

Kuttruff

(1991), “Room Acoustics”, third edition, Elsevier Applied Science, London and New York.

Knudsen

V.O.

and Harris

C.M.

(1950). “Acoustical Designing in Architecture”, Wiley, New York.

Yousif

D.J.

(1983). “Design and performance of an electroacoustic reflector for use in auditoria”, PhD thesis. University of Southampton.

Schroeder

M.R.

(1964). “Improvement of Acoustic-Feedback Stability by Frequency Shifting”. J. Acoustic. Soc. Am., 36(9): 1718.

Barron

(1993). “Auditorium Acoustics and Architectural Design”, first edition, E & F.N. Spon, London.

Houtgast

and Steeneken

H.J.M.

(1973). “The modulation transfer function in room acoustics as a predictor of speech intelligibility”, Acustica, 28: 66-73.

Houtgast

and Steeneken

H.J.M.

(1985). “A review of the MTF concept in room acoustics and its use for estimating speech intelligibility in auditoria”, J. Acoust. Soc. Am., 77(3): 1069-1077.

Plomp

, Houtgast

and Steeneken

H.J.M.

(1980), “Predicting Speech Intelligibility in Rooms from the Modulation Transfer Function, Part II”, Acustica, 46: 75.

van Maercke

and Martin

(1993), “The prediction of echograms and impulse responses within the Epidaure software”, Applied Acoustics, 38: 93-114.

10.

Naylor

G.M.

(1993), “ODEON – Another hybrid room acoustical model”, Applied Acoustics, 38: 131-143.