THURSDAY MORNING, 16 MAY 2019 FRENCH, 8:15 A.M. TO 11:35 A.M. Session 4aAA Architectural Acoustics, Signal Processing in Acoustics, and Noise: Methods and Techniques Used for Simulation of Room Acoustics Bruce C. Olson, Cochair AFMG Services North America LLC, 8717 Humboldt Avenue North, Brooklyn Park, MN 55444 Ana M. Jaramillo, Cochair Ahnert Feistel Media Group, 8717 Humboldt Ave. N, Brooklyn Park, MN 55444 Chair’s Introduction—8:15 Invited Papers 8:20 4aAA1. Level of detail in room-acoustic simulation. Michael Vorlaender (ITA, RWTH Aachen Univ., Kopernikusstr. 5, Aachen 52056, Germany, [email protected]) The quality of present-day room acoustic simulations depends on the quality of the boundary conditions and of the underlying CAD room models. A “high-resolution” room model does not mean that it needs to have a visually perfect geometrical fine structure. To our experience, the required resolution of objects or surfaces does not need to be higher than about 1 m. In this presentation, an auralization engine is briefly introduced which uses a set of models of the same room but with a graduated level of detail (LOD). These different models can account for more physical correctness especially for very low-frequency specular reflections. Furthermore, a good estimate of scattering coefficients is essential. The relevance of the uncertainty of scattering coefficient data is discussed in a review on perception tests with varied surface scattering. Finally, guidelines for creation of CAD models are proposed. 8:40 4aAA2. Should we still rely on statistical calculations for the prediction of reverberation time? Ana M. Jaramillo (AFMG Services North America, 8717 Humboldt Ave. N, Brooklyn Park, MN 55444, [email protected]) and Bruce Olson (Olson Sound Design, LLC, Brooklyn Park, MN) Based on the conditions for the use of the most commonly used reverberation time equations, we have created room examples in EASE to compare how they correlate with ray tracing predictions and established a guideline on when we can rely on simple statistical predictions. The results show that statistical predictions are not always accurate, and the differences do not always go in the same direc- tion, making it impossible to simply account for the under/over-estimation of the method. 9:00 4aAA3. Modelling the effects of spectators on speech intelligibility in a typical soccer stadium. Ross Hammond (School of Mathe- 4a THU. AM matics, Computing and Electronics, Univ. of Derby, Derby, United Kingdom), Peter Mapp (Peter Mapp Assoc., Copford, Colchester CO6 1LG, United Kingdom, [email protected]), and Adam J. Hill (School of Mathematics, Computing and Electronics, Univ. of Derby, Derby, United Kingdom) Public address system performance is frequently simulated using acoustic computer models to assess coverage and predict potential intelligibility. Simulations are most-often completed in unoccupied spaces as this provides worst-case scenario intelligibility due to the reduced absorption. When the typical 0.5 speech transmission index (STI) criterion cannot be achieved in voice alarm systems, due to design difficulties, justification must be made to allow contractual obligations to be met. An expected increase in STI with occupancy can be used as an explanation, though the associated increase in noise levels must also be considered. However, numerous approaches exist when modelling the people which can produce significant discrepancies. This work demonstrates typical changes in STI for differ- ent spectator conditions in a calibrated stadium computer model. This includes different audience modelling approaches, distribution, capacity, posture (standing/seated), and atmospheric conditions. The effects of ambient noise are also considered. The results can be used to approximate expected changes in STI caused by different spectator conditions. 1853 J. Acoust. Soc. Am., Vol. 145, No. 3, Pt. 2, March 2019 177th Meeting: Acoustical Society of America 1853 9:20 4aAA4. Acoustics simulations to inform the designs of large worship and entertainment spaces to the client and contractor. David S. Woolworth (Roland, Woolworth & Assoc., 356 CR 102, Oxford, MS 38655, [email protected]) Computer based acoustical simulations can quickly communicate important information in visual and audible formats that have a strong and immediate impact on the non-acoustician decision makers and designers of a project. Two large spaces were modeled (>6000 m3), one renovation, one new construction; simulations were used to help better understand the consequences of different design approaches for amplified sound and acoustical design, as well as handing value engineering response in a timely manner. Attention is given to the modeling’s role in helping to sort out the paradigms of perception of the project team and then to inform the design options of the clients and end users. 9:40 4aAA5. Use and misuse of auralization. Wolfgang Ahnert (Ahnert Feistel Media Group, Arkonastr. 45-49, Berlin D-13189, Germany, [email protected]) Auralization was developed as a tool in the 30s. The historic overview over this development starts by using scale models as a design tool which is used until now. Here, the needed components are explained, and the pros and cons will be discussed. With the use of com- puter simulation in the end of the 60s, the presentation of auralized files started around 1990 first considered as a toy. Today the use of auralization is widespread. This paper describes the development of the technical tools to present auralized signals available for binaural reproduction without and with head tracker and by using loudspeaker reproduction without and with crosstalk cancelation. Nowadays, Acoustic labs with Ambisonics reproduction or similar technologies are used. In this presentation, the advantages of auralization are named including all positive properties to demonstrate the achieved simulation results to different client groups. But also, the misuse of auralization is shown in detail by using found examples. 10:00–10:15 Break 10:15 4aAA6. New tools to auralize simulation results with EASE 5.0. Tobias Behrens (ADA Acoust. & Media Consultants GmbH, Arko- nastr. 45-49, Berlin 13189, Germany, [email protected]), Khaled Wazaefi (ADA Acoust. & Media Consultants GmbH, Berlin, Deutschland, Germany), and Wolfgang Ahnert (AFMG Ahnert Feistel Media Group, Berlin, Germany) The new software package in EASE allows the production of binaural files to check the quality of the simulation results and to make these results audible for music or speech samples in real time. Also, tests with head trackers have been made. Since 5 years, the software allows generating B-format files of second order. To reproduce sound fields based on these 9 files, a sound lab has been built. This lab will be represented and explained. A post-processing software for EASE allows to reproduce not only the calculated simulation files but in comparison also measured files by using the microphone Ambeo VR. Additionally, VR glasses generate realistic 3D-visuals, in the same model as used for acoustic simulation. That way realized acoustic treatments in the room become visible and audio-visual repre- sentations are possible. Results for comparison between simulated rooms and measured real rooms will be discussed. Contributed Papers 10:35 10:50 4aAA7. Room acoustic simulation as a means to affect a musical compo- 4aAA8. An analysis of ceiling geometry within active learning sition for a location specific performance. Edwin S. Skorski (Interior classrooms. Edwin S. Skorski (Interior Architecture, Univ. of North Caro- Architecture, Univ. of North Carolina - Greensboro, 102 Gatewood Studio lina - Greensboro, 102 Gatewood Studio Arts Bld., 527 Highland Ave., Arts Bld., 527 Highland Ave., Greensboro, NC 48859, skors1es@cmich. Greensboro, NC 48859, [email protected]) edu) and Steven J. Landis (Music, Univ. of North Carolina - Greensboro, The architectural designs and furnishing of active learning classroom Greensboro, NC) spaces are playing an increasingly important role in the facilitation of mod- Computer model simulations of existing interior spaces are often generated ern educational methods. Traditional static classroom spaces effectively to document and analyze room acoustic characteristics. In this case study, a support a lecture style of teaching where student participation is passive. large, multi-tiered public atrium is analyzed for its potential use as a perform- Due to their rigid space plan, they are poor at encouraging interaction ance space. Furthermore, the analysis is also used to transform an existing mu- among students and teachers. Conversely, active learning spaces promote sical composition into a location specific performance piece. The computer innovative teaching methods where quick room re-configuration allows for simulation highlights acoustic characteristics believed to be good for musical discussion groups of various sizes, the simultaneous use of a variety of performance as well as those considered defects. Taking into account the teaching methods, and provides greater opportunity for the incorporation of unique room acoustic qualities of this non-traditional performance space, an technology into the classroom. From a room acoustic perspective, the existing musical composition is rewritten resulting in a space-dependent increase in room arrangement flexibility leads to a complex acoustic envi- arrangement. Musical variables transformed due to the analysis include tempo, ronment where the spatial relationship