AES Rome 2013
Paper Session P9

Sunday, May 5, 14:30 — 18:00 (Sala Carducci)

Paper Session: P9 - Room Acoustics

Chris Baume, BBC Research and Development - London, UK

P9-1 Various Applications of Active Field ControlTakayuki Watanabe, Yamaha Corp. - Hamamatsu, Shizuoka, Japan; Masahiro Ikeda, Yamaha Corporation - Hamamatsu, Shizuoka, Japan
The Active Field Control system is an acoustic enhancement system that was developed to improve the acoustic conditions of a space so as to match the acoustic conditions required for a variety of different types of performance programs. This system is unique in that it uses FIR filtering to ensure freedom of control and the concept of spatial averaging to achieve stability with a lower number of channels than comparative systems. This system has been used in over 70 projects in both the U.S. and Japan. This paper will provide an overview of the characteristics of the system and examples of how the system has been applied.
Convention Paper 8859 (Purchase now)

P9-2 Comparative Acoustic Measurements: Spherical Sound Source vs. DodecahedronPlamen Valtchev, Univox - Sofia, Bulgaria; Denise Gerganova, Spherovox
Spherical sound source, consisting of a pair of coaxial loudspeakers and a pair of compression drivers and radiating into a common radially expanding horn, is used for acoustic measurements of rooms for speech and music. For exactly the same source-microphone pair positions, comparative measurements are made with a typical dodecahedron, keeping the same microphone technique, identical signals, and recording hardware under the same measuring conditions. Several software programs were used for evaluation of the acoustical parameters extracted from impulse responses. Parameters are presented in tables and graphics for better sound source comparisons. Spherical sound source reveals higher dynamic range and perfectly repeatable parameters with source rotation, which is in contrast to dodecahedron, where rotation steps resulted in some parameters’ deviation.
Convention Paper 8860 (Purchase now)

P9-3 Archaeoacoustics: An Introduction—A New Take on an Old ScienceLise-Lotte Tjellesen, CLARP - London, UK; Karen Colligan, CLARP - London, UK
What is Archaeoacoustics and how is it defined? This paper will discuss the history and varying aspects of the discipline of archaeoacoustics, i.e., sound that has been measured, modeled, and analyzed with modern techniques in and around Ancient sites, temple complexes, and standing stones. Piecing together sound environments from a long lost past it is brought to life as a tool for archaeologists and historians. This paper will provide a general overview of some of the most prolific studies to date, discuss some measurement and modeling methods, and discuss where archaeoacoustics may be headed in the future and what purpose it serves in academia.
Convention Paper 8861 (Purchase now)

P9-4 Scattering Effects in Small-Rooms: From Time and Frequency Analysis to Psychoacoustic InvestigationLorenzo Rizzi, Suono e Vita - Acoustic Engineering - Lecco, Italy; Gabriele Ghelfi, Suono e Vita - Acoustic Engineering - Lecco, Italy
This work continues the authors’ effort to optimize a DSP tool for extrapolating from R.I.R. information regarding mixing time and sound scattering effects with in-situ measurements. Confirming past thesis, a new specific experiment allowed to scrutinize the effects of QRD scattering panels over non-Sabinian environments, both in frequency and in time domain. Listening tests have been performed to investigate perception of scattering panels effecting small-room acoustic quality. The sound diffusion properties have been searched with specific headphone auralization interviews, convolving known R.I.R.s with anechoic musical samples and correlating calculated data to psychoacoustic responses. The results validate the known effect on close field recording in small rooms for music and recording giving new insights.
Convention Paper 8862 (Purchase now)

P9-5 The Effects of Temporal Alignment of Loudspeaker Array Elements on Speech IntelligibilityTimothy J. Ryan, Webster University - St. Louis, MO, USA; Richard King, McGill University - Montreal, Quebec, Canada; The Centre for Interdisciplinary Research in Music Media and Technology - Montreal, Quebec, Canada; Jonas Braasch, Rensselaer Polytechnic Institute - Troy, NY, USA; William L. Martens, University of Sydney - Sydney, NSW, Australia
The effects of multiple arrivals on the intelligibility of speech produced by live-sound reinforcement systems are examined. Investigated variables include the delay time between arrivals from multiple loudspeakers within an array and the geometry and type of array. Subjective testing, using captured binaural recordings of the Modified Rhyme Test under various treatment conditions, was carried out to determine the first- and second-order effects of the two experimental variables. Results indicate that different interaction effects exist for different amounts of delay offset.
Convention Paper 8863 (Purchase now)

P9-6 Some Practical Aspects of STI Measurement and PredictionPeter Mapp, Peter Mapp Associates - Colchester, Essex, UK
The Speech Transmission Index (STI) has become the internationally accepted method of testing and assessing the potential intelligibility of sound systems. The technique is standardized in IEC 60268-16, however, it is not a flawless technique. The paper discusses a number of common mechanisms that can affect the accuracy of STI measurements and predictions. In particular it is shown that RaSTI is a poor predictor of STI in many sound system applications and that the standard speech spectrum assumed by STI often does not replicate the speech spectrum of real announcements and is not in good agreement with other speech spectrum studies. The effects on STI measurements of common signal processing techniques such as equalization, compression, and AGC are also demonstrated and the implications discussed. The simplified STI derivative STIPA is shown to be a more robust method of assessing sound systems than RaSTI and when applied as a direct measurement method can have significant advantages over Impulse Response-based STI measurement techniques.
Convention Paper 8864 (Purchase now)

P9-7 Combined Quasi-Anechoic and In-Room Equalization of Loudspeaker ResponsesBalazs Bank, Budapest University of Technology and Economics - Budapest, Hungary
This paper presents a combined approach to loudspeaker/room response equalization based on simple in-room measurements. In the first step, the anechoic response of the loudspeaker, which mostly determines localization and timbre perception, is equalized with a low-order non-minimum phase equalizer. This is actually done using the gated in-room response, which of course means that the equalization is incorrect at low frequencies where the gate time is shorter than the anechoic impulse response. In the second step, a standard, fractional-octave resolution minimum-phase equalizer is designed based on the in-room response pre-equalized with the quasi-anechoic equalizer. This second step, in addition to correcting the room response, automatically compensates the low-frequency errors made in the quasi-anechoic equalizer design when we were using gated responses.
Convention Paper 8826 (Purchase now)

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