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Tuesday Morning, 28 October 2014 Marriott 7/8, 7:55 A.M. to 12:00 Noon

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Tuesday Morning, 28 October 2014 Marriott 7/8, 7:55 A.M. to 12:00 Noon TUESDAY MORNING, 28 OCTOBER 2014 MARRIOTT 7/8, 7:55 A.M. TO 12:00 NOON Session 2aAA Architectural Acoustics and Engineering Acoustics: Architectural Acoustics and Audio I K. Anthony Hoover, Cochair McKay Conant Hoover, 5655 Lindero Canyon Road, Suite 325, Westlake Village, CA 91362 Alexander U. Case, Cochair Sound Recording Technology, University of Massachusetts Lowell, 35 Wilder St., Suite 3, Lowell, MA 01854 Chair’s Introduction—7:55 Invited Papers 8:00 2aAA1. Excessive reverberance in an outdoor amphitheater. K. Anthony Hoover (McKay Conant Hoover, 5655 Lindero Canyon Rd., Ste. 325, Westlake Village, CA 91362, [email protected]) The historic Ford Theatre in Hollywood, CA, is undergoing an overall renovation and expansion. Its centerpiece is the inexplicably asymmetrical 1200 seat outdoor amphitheater, built of concrete in 1931 after the original 1920 wood structure was destroyed by a brush fire in 1929, and well before the adjacent Hollywood Freeway was nearly as noisy as now. Renovation includes reorienting seating for better symmetry while maintaining the historic concrete, and improving audio, lighting, and support spaces. Sited within an arroyo over- looking a busy highway, and in view of the Hollywood Bowl, the new design features an expanded “sound wall” that will help to miti- gate highway noise while providing optimal lighting and control positions. New sound-absorptive treatments will address the Ford’s excessive reverberation, currently more than might be anticipated for an entirely outdoor space. The remarkably uniform distribution of ambient noise and apparent contributions by the arroyo to the reverberation will be discussed, along with assorted design challenges. 8:20 2aAA2. Room acoustics analysis, recordings of real and simulated performances, and integration of an acoustic shell mock up with performers for evaluation of a choir shell design. David S. Woolworth (Oxford Acoust., 356 CR 102, Oxford, MS 38655, [email protected]) The current renovation of the 1883 Galloway Memorial Methodist Church required the repair and replacement of a number of room finishes, as well as resolution of acoustic problems related to their choir loft. This paper will present the various approaches used to determine the best course of action using primarily an in-situ analysis that includes construction mockups, simulated sources, and critical listening. 8:40 2aAA3. A decade later: What we’ve learned from The Pritzker Pavilion at Millennium Park. Jonathan Laney, Greg Miller, Scott Pfeiffer, and Carl Giegold (Threshold Acoust., 53 W Jackson Blvd., Ste. 815, Chicago, IL 60604, [email protected]) Each design and construction process yields a building and systems that respond to a particular client at a particular time. We launch these projects into the wild and all too frequently know little of their daily lives and annual cycles after that. Occasionally, though, we have the opportunity to stay close enough to watch a project wear in, weather (sometimes literally), and respond to changing client and patron dynamics over time. Such is the case with the reinforcement and enhancement systems at the Pritzker Pavilion in Chicago’s Mil- lennium Park. On a fine-grained scale, each outdoor loudspeaker is individually inspected for its condition at the end of each season. Sig- nal-processing and amplification equipment is evaluated as well, so the overall system is maintained at a high degree of readiness and reliability. Strengths and weaknesses of these components thereby reveal themselves over time. We will discuss these technical aspects as well as changing audience behaviors, modifications made for special events, and the ways all of these factors inform the future of audio (and video) in the Park. 2114 J. Acoust. Soc. Am., Vol. 136, No. 4, Pt. 2, October 2014 168th Meeting: Acoustical Society of America 2114 9:00 2aAA4. An electro-acoustic conundrum—Improving the listening experience at the Park Avenue Armory. Steve Barbar (E-coustic Systems, 30 Dunbarton Rd., Belmont, MA 02478, [email protected]) and Paul Scarbrough (Akustiks, South Norwalk, CT) Larger than a hanger for a commercial airliner, the Park Avenue Armory occupies an entire city block in midtown Manhattan. Its massive internal volume generates reverberation time in excess of three seconds. However, it functions as a true multi-purpose venue with programming that includes dramatic performances produced by the Manchester International Festival, and musical performances sponsored by Lincoln Center. We will discuss the unique nature of the venue as well as the tools and techniques employed in staging dif- ferent productions. 9:20 2aAA5. Sound reinforcement in an acoustically challenging multipurpose space. Deb Britton (K2 Audio, 4900 Pearl East Circle, Ste. 201E, Boulder, CO 80301, [email protected]) Often times, sound system designers are dealt less than ideal cards: design a sound reinforcement system that will provide great speech intelligibility, in a highly reverberant space, without modifying any of the architectural finishes. While this can certainly be a challenge, add to those prerequisites, the additional complication of the sound system serving a multi-purpose use, where different types of presentations must take place in different locations in the space, and with varying audience sizes. This paper presents a case study of such a scenario, and describes the approach taken in order to achieve the client’s goals. 9:40 2aAA6. Comparison of source stimulus input method on measured speech transmission index values of sound reinforcement 2a TUE. AM systems. Neil T. Shade (Acoust. Design Collaborative, Ltd., 7509 Lhirondelle Club Rd., Ruxton, MD 21204, [email protected]) One purpose of a sound reinforcement system is to increase the talker’s speech intelligibility. A common metric for speech intelligi- bility evaluation is the Speech Transmission Index (STI) defined by IEC-60268-16 Revision 4. The STI of a sound reinforcement system can be measured by inputting a stimulus signal into the sound system, which is modified by the system electronics, and radiated by the sound system loudspeakers to the audience seats. The stimulus signal can be input via a line level connection to the sound system or by playing the stimulus signal through a small loudspeaker that is picked-up by a sound system microphone. This latter approach factors the entire sound system signal chain from microphone input to loudspeaker output. STI measurements were performed on two sound systems, one in a reverberant room and the other in relatively non-reverberant room. Measurement results compare both signal input techniques using omnidirectional and hypercardioid sound system microphones and three loudspeakers claimed to be designed to have directivity characteristics similar to the human voice. 10:00–10:20 Break 10:20 2aAA7. Enhancements in technology for improving access to active acoustic solutions in multipurpose venues. Ronald Freiheit (Wenger Corp., 555 Park Dr., Owatonna, MN 55060, [email protected]) With advancements in digital signal processing technology and higher integration of functionality, access to active acoustics systems for multipurpose venues has been enhanced. One of the challenges with active acoustics systems in multipurpose venues is having enough control over the various acoustic environments within the same room (e.g., under balcony versus over balcony). Each area may require its own signal processing and control to be effective. Increasing the signal processing capacity to address these different environ- ments will provide a more effective integration of the system in the room. A new signal processing platform with the flexibility to meet these needs is discussed. The new platform addresses multiple areas with concurrent processing and is integrated with a digital audio buss and a network-based control system. The system is flexible in its ability to easily expand to meet the needs of a variety of environ- ments. Enhancing integration and flexibility of scale accelerates the potential for active systems with an attractive financial point of entry. 10:40 2aAA8. Sound levels and the risk of hearing damage at a large music college. Thomas J. Plsek (Brass, Berklee College of Music, MS 1140 Brass, 1140 Boylston St., Boston, MA 02215, [email protected]) For a recent sabbatical from Berklee College of Music, my project was to study hearing loss especially among student and faculty musicians and to measure sound levels in various performance situation ranging from rehearsals to classes/labs to actual public perform- ances. The National Institute for Occupational Safety and Health (NIOSH) recommendations (85 dBA criterion with a 3 dB exchange rate) were used to determine the daily noise dose obtained in each of the situations. In about half of the situations 100% or more of the daily noise was reached. More measuring of actual levels reached is needed as are noise dosimetry measurements over an active 12–16 hour day. 11:00 2aAA9. Development of a tunable absorber/diffuser using micro-perforated panels. Matthew S. Hildebrand (Wenger Corp., 555 Park Dr., Owatonna, MN 55060, [email protected]) Shared rehearsal spaces are an all-too-common compromise in music education, pitting vocal, and instrumental ensembles against each other for desirable room acoustics. More than ever, adjustable acoustics are needed in music spaces. An innovative new acoustic panel system was developed with this need for flexibility in mind. Providing variable sound absorption
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