Downloaded from orbit.dtu.dk on: Oct 01, 2021 Investigating the build-up of precedence effect using reflection masking Hartcher-O'Brien, Jessica; Buchholz, Jörg Published in: Journal of the Acoustical Society of America Publication date: 2006 Document Version Publisher's PDF, also known as Version of record Link back to DTU Orbit Citation (APA): Hartcher-O'Brien, J., & Buchholz, J. (2006). Investigating the build-up of precedence effect using reflection masking. In Journal of the Acoustical Society of America (Vol. 120). Acoustical Society of America. General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. Users may download and print one copy of any publication from the public portal for the purpose of private study or research. You may not further distribute the material or use it for any profit-making activity or commercial gain You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. WEDNESDAY MORNING, 29 NOVEMBER 2006 LANAI ROOM, 7:30 TO 11:55 A.M. Session 2aAA Architectural Acoustics: Acoustics of Large Indoor and Outdoor Performance Spaces I Daniel R. Raichel, Cochair 2727 Moore Ln., Fort Collins, CO 80526 Toshiki Hanyu, Cochair Nihon Univ., Narashinodai, Funabashi, Chiba 274-8501, Japan Chair’s Introduction—7:30 Invited Papers 7:35 2aAA1. Differences in dealing with the acoustics of large outdoor and indoor listening spaces. Daniel R. Raichel ͑Eilar Assoc. and the Graudate Ctr., CUNY, 2727 Moore Ln., Fort Collins, CO 80526, [email protected]͒ It was perhaps fortuitous that Wallace Clement Sabine’s first consulting assignment from the Harvard Board of Overseers, the execution of which proved to be seminal in the history of architectural acoustics, entailed an indoor facility. The problems of dealing with outdoor performance areas are considerably greater than those encountered in indoor spaces. Indoor spaces provide surface reflections and absorption of sound, both of which can be manipulated through proper design to yield the desired results with respect to reverberation time and sound dispersion. In the case of outdoor performing areas, there are no reflective surfaces ͑except in the cases of certain amphitheaters͒, and the need for sound amplification is often necessitated. A reflective bandshell is generally required to direct the program material toward the audience. The lack of wall reflections tends to result in a lack of musical sonority that is usually present in a well-designed indoor auditorium. A number of specific problems with interior and outdoor spaces and modern approaches toward resolving acoustical problems of large listening areas will be discussed. 7:55 2aAA2. Prediction of reverberation by stochastic processes in a forest: Creation of reverberation in an outdoor performance space. Toshiki Hanyu and Katsuaki Sekiguchi ͑Nihon Univ., Narashinodai, Funabashi, 274-8501, Chiba, Japan, [email protected]͒ A forest is an outdoor space. For that reason, reverberation formulas of indoor spaces cannot be used when predicting forest reverberation. As a matter of fact, because the level decay curve of the reverberant sound produced in a forest is nonlinear, the concept of reverberation time is inapplicable. We clarified that reverberation of a forest is expressible as a Wiener process ͑Brownian motion͒, which is a stochastic process, and we derived the formula of reverberation of a forest based on that fact. In this study, Monte Carlo simulation was also carried out. Results clarified the following. ͑1͒ The energy decay curve of the reverberation sound of a forest becomes a straight line on the logarithmic scale of time and energy; its line gradient is Ϫ2. ͑2͒ At a point far from a sound source, the reverberant sound energy increases first and begins to decrease after some period. ͑3͒ When the mean-free path is short, the sound level of reverberation becomes high. Furthermore, we devised some methods of generating reverberation in outdoor space using the forest reverberation mechanism. For example, a proposed reverberation wall can produce reverberations using only one wall incor- porating sound scatterers. 8:15 2aAA3. Large outdoor performance venues: Acoustical lessons learned. William J. Cavanaugh and K. Anthony Hoover ͑327F Boston Post Rd., Sudbury, MA 01776͒ The Tweeter Center for the Performing Arts ͑formerly Great Woods͒ in Mansfield, MA, off Interstate 495, midway between Boston and Providence, accommodates 19 900 patrons and offers 75 to 85 performances each year between 15 May and 15 October. The Pittsburgh Symphony Orchestra inaugurated Tweeter Center’s first concert season in June 1986, and The Center hosted the PSO as its summer home for three additional seasons. The Center has hosted performances from solo comedians to symphonic orchestras and rock bands, featuring such diverse acts as the Boston Pops, James Taylor, Phish, and The Kinks. The acoustical lessons learned over two decades of operation are described. The Center has served as a model for the design and operation of facilities in the 20 000-capacity range, including the often difficult issues of controlling excessive amplified sound transmission to residential neigh- bors, as well as assuring good listening conditions for patrons and performers alike. 3052 J. Acoust. Soc. Am., Vol. 120, No. 5, Pt. 2, November 2006 Fourth Joint Meeting: ASA and ASJ 3052 8:35 2aAA4. Design of public address system for emergency evacuation in a tunnel. Sakae Yokoyama, Hideki Tachibana ͑Chiba Inst. of Technol., 2-17-1 Tsudanuma, Narashino-city, Chiba, 275-0016, Japan, [email protected]͒, Shinichi Sakamoto ͑Univ. of Tokyo, Meguro-ku, Tokyo, 153-8505, Japan͒, and Seiya Tazawa ͑Metropolitan Expressway Co. Ltd., Chiyoda-ku, Tokyo, 100-8930, Japan͒ As a means to improve speech intelligibility of a public address PA system for emergency evacuation announcement in a tunnel, the authors have been investigating the application of the successive time-delay technique and have performed the experiments in an actual tunnel. In the experiments, the effect of the technique has been examined by comparing the difference of speech intelligibility between the conditions with/without time delay. For the design of the PA system in a reverberant tunnel, four kinds of psycho- acoustical experiments on speech intelligibility were performed in an anechoic room using the six-channel recording/reproduction technique and the following results have been obtained: ͑1͒ the successive time-delay technique is very effective to improve the speech intelligibility in a tunnel, ͑2͒ the system is considerably robust against the error in the delay time, ͑3͒ the speech intelligibility improves with the increase of the speech-rate but it should be suitable for such a tense situation as fire emergency, and ͑4͒ in order to further improve the speech intelligibility, it is necessary to control the reverberation in the tunnel by any sound absorption treatment. In this paper, the outline of the field experiment and the results of subjective experiments are introduced. 8:55 2aAA5. The Jay Pritzker Music Pavilion at Millennium Park, part 1: Design and construction. Richard Talaske ͑TALASKE, 105 N. Oak Park Ave., Oak Park, IL 60301͒ The acoustic and audio system design for the Pritzker Pavilion represents a leap forward in the outdoor listening experience. The venue offers superior sound experiences to audiences of 11 000 using audio reinforcement and acoustic enhancement systems to 2a WED. AM support all types of musical performances, particularly for the resident Grant Park Music Festival orchestra. With reliance on the audio systems to project and envelop the audience in sound, the design of the stage enclosure was able to focus on the acoustic quality for the ensemble, a rare opportunity in outdoor facilities. The stage enclosure design includes variable acoustic devices and has an emphasis on intraensemble communication. This presentation will discuss the design of the stage enclosure, the trellis-supported audio systems, and the ways in which the facility is used by resident and visiting musical performers. 9:15 2aAA6. The Jay Pritzker Music Pavilion at Millennium Park, part 2: Research and testing. Gregory Miller, Richard Talaske, Byron Harrison, Evelyn Way ͑TALASKE, 105 N. Oak Park Ave., Oak Park, IL 60301͒, Lily Wang, David Bradley, and Craig Johnson ͑Univ. of Nebraska-Lincoln, Omaha, NE 68182-0681͒ The design of the Pritzker Pavilion includes a number of innovative acoustic and audio elements. Two of these elements, the resilient orchestra riser system and the acoustic enhancement system, will be discussed in this presentation. Research previously presented to the ASA ͓Hoffman et.al., 141st meeting of the ASA͒ was used in the design of the orchestra riser system at the Pritzker Pavilion. This presentation discusses the field tests that were conducted to assess vibration transfer across the surface of the riser system. Comparison is made to previous research and anticipated results. Subjective evaluations by orchestra members will also be discussed. The acoustic enhancement system is a specialized audio system, separate from the main reinforcement audio system,