AES Paris 2016
Paper Session P4
P4 - Room Acoustics
Saturday, June 4, 13:30 — 16:30 (Room 352B)
Chair:
Ben Kok, BEN KOK - acoustic consulting - Uden, The Netherlands
P4-1 Small-Rooms Dedicated to Music: From Room Response Analysis to Acoustic Design—Lorenzo Rizzi, Suono e Vita - Acoustic Engineering - Lecco, Italy; Gabriele Ghelfi, Suono e Vita - Acoustic Engineering - Lecco, Italy; Maurizio Santini, Università degli Studi di Bergamo - Bergamo, Italy
Reviewing elements of on-field professional experience gained by the authors in the analysis of small-rooms dedicated to music, case studies offered by the everyday working practice allow to deal with specific situations, these are seldom described by usual theoretical models and literature. Using the analysis procedure developed and refined by authors, it is possible to investigate the characteristics of the acoustic response of the small-rooms with more detail. In this paper case studies of particular interest will be described: different small-room phenomena will be shown in the reported measurements.
[Also a poster—see session P8-2]
Convention Paper 9502 (Purchase now)
P4-2 Direction of Late Reverberation and Envelopment in Two Reproduced Berlin Concert Halls—Winfried Lachenmayr, Mueller-BBM - Munich, Germany; Musikhochschule Detmold; Aki Haapaniemi, Aalto University School of Science - Aalto, Finland; Tapio Lokki, Aalto University - Aalto, Finland
Most studies on the influence of the direction of late reverberation on listener envelopment (LEV) in concert halls have been conducted in laboratory conditions, i.e., where synthetic sound fields and a relatively limited number of loudspeakers were used to approximate a real, spatially quite complex acoustic situation. This study approaches LEV from the real acoustics. The late part of the sound field of two measured concert halls Berlin Konzerthaus and Berlin Philharmonie, auralized with a state-of-the-art reproduction method, is altered virtually regarding its’ direction. Results suggest that the figure-of-eight weighting applied in late lateral level LJ for predicting envelopment is underestimating the importance of reverberation from directions such as ceiling and rear.
Convention Paper 9503 (Purchase now)
P4-3 Electronic Shell—Improvement of Room Acoustics without Orchestra Shell Utilizing Active Field Control—Takayuki Watanabe, Yamaha Corp. - Hamamatsu, Shizuoka, Japan; Hideo Miyazaki, Yamaha Corp. - Hamamatsu, Shizuoka, Japan; Masahiro Ikeda, Yamaha Corporation - Hamamatsu, Shizuoka, Japan
This paper introduces an example of Electronic Shell acoustic enhancement system that was installed in a multi-purpose hall without an orchestra shell. The system is based on the concept of Active Field Control using electroacoustic means. The three objectives of this system were (1) the enhancement of early reflection for performers, (2) the increase of the reverberation time and the total sound energy on stage, and (3) the enhancement of early reflection in the audience area. The application of this system showed an improvement of about 1 to 2 dB in STearly and more than 2 dB in G in the audience area, which is equivalent or better performance than simple mobile typed orchestra shell.
[Also a Poster—See Session P8-3]
Convention Paper 9504 (Purchase now)
P4-4 Experimental Assessment of Low-Frequency Electroacoustic Absorbers for Modal Equalization in Actual Listening Rooms—Etienne Rivet, Ecole polytechnique fédérale de Lausanne (EPFL) - Lausanne, Switzerland; Sami Karkar, Ecole Polytechnique Fédérale de Lausanne (EPFL) - Lausanne, Switzerland; Hervé Lissek, Ecole Polytechnique Fédérale de Lausanne (EPFL) - Lausanne, Switzerland; Torje Nikolai Thorsen, Goldmund International - Monaco, Monaco; Véronique Adam, Goldmund International - Monaco, Monaco
In listening rooms, low-frequency modal resonances lead to uneven distributions in space and frequency of the acoustic energy, as well as an alteration of the temporal behavior of the original music content. While usual absorption techniques have severe limitations for reducing the negative impact of room modes, the authors have previously proposed the use of electroacoustic absorbers for room modal equalization. This device consists of a current-driven, closed-box loudspeaker associated to a hybrid sensor-/shunt-based impedance control. In this communication we assess the performance of these electroacoustic absorbers in actual listening rooms, by measuring frequency responses at different locations, as well as their modal decay times. The electroacoustic absorbers perform as expected and the room modal equalization is clearly improved in the low-frequency range.
Convention Paper 9505 (Purchase now)
P4-5 Modeling Non-Shoebox Shaped Rooms with the Mode Matching Method—Bjørn Kolbrek, Norwegian University of Science and Technology - Trondheim, Norway; U. Peter Svensson, NTNU - Trondheim, Norway
When a room is not shoebox shaped, usually no analytical expressions exist for the determination of resonance frequencies and mode shapes. One option is to employ the Finite Element Method (FEM). In this paper an alternative method, the Mode Matching Method (MMM), is used to compute the transfer function and sound field of a non-shoebox shaped room with rigid walls and is compared to an FEM solution. The two methods show excellent agreement.
Also a poster—see session P8-7]
Convention Paper 9506 (Purchase now)
P4-6 Room Acoustic Measurements Using a High SPL Dodecahedron—Dario D'Orazio, University of Bologna - Bologna, Italy; Simona De Cesaris, University of Bologna - Bologna, Italy; Paolo Guidorzi, University of Bologna - Bologna, Italy; Luca Barbaresi, University of Bologna - Bologna, Italy; Massimo Garai, University of Bologna - Bologna, Italy; Roberto Magalotti, B&C Speakers S.p.A. - Bagno a Ripoli (FI), Italy
In this paper a dodecahedron with high powered loudspeakers is presented. The source is designed to allow high SPL with very low distortion. By comparing the prototype with a reference sound source, the high SPL dodecahedron show a flat frequency response over the 80 ÷ 5000 Hz one third octave bands, enough to meet all the ISO 3382 criteria. Laboratory measurements have been performed to test the performances and the robustness of the dodecahedron using different techniques at different sound pressure levels and background noises. The prototype allows a good signal-to-noise ratio of the impulse response also when 75 dB of stationary noise is added during the measurements.
Convention Paper 9507 (Purchase now)
