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Computer Modeling and Prediction of Room Acoustics

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Full-Text Articles in Acoustics, Dynamics, and Controls

Effects Of Changing The Amount Of Absorption In A Computer Model Of Queen’S Hall, Copenhagen, Denmark, Michelle C Vigeant, Lily M. Wang, Jens Holger Rindel Jun 2014

Effects Of Changing The Amount Of Absorption In A Computer Model Of Queen’S Hall, Copenhagen, Denmark, Michelle C Vigeant, Lily M. Wang, Jens Holger Rindel

Lily M Wang

Room acoustics modelling and auralizations are very useful tools in the design of acoustically sensitive spaces. One area of improvement for auralizations is the method of modelling the source directivity. A new method to incorporate source directivity is multi-channel auralizations. This study first evaluates the objective effects of using four and thirteen channel impulse responses in an ODEON model of Queen’s Hall, where the actual variable absorption is changed within the model. Analyses of the results reveal great differences in the objective parameters of reverberation time and sound pressure level across each channel’s impulse response. Subjective studies were then conducted …


Investigations Of Multi-Channel Auralization Technique For Various Orchestra Arrangements, With Phase-Shifted String Sections, Michelle C Vigeant, Lily M. Wang Jun 2014

Investigations Of Multi-Channel Auralization Technique For Various Orchestra Arrangements, With Phase-Shifted String Sections, Michelle C Vigeant, Lily M. Wang

Lily M Wang

An orchestra can be simulated in room acoustics computer modelling using a variety of methods, ranging from a single omni-directional source to individual sources of all instruments. This study utilizes the method of individual sources for each instrument, but with reduced source representation for the string sections. The anechoic recordings used in this investigation are five-channel recordings, which capture the source directivity of the individual instruments. For each string section, the individual anechoic recordings were phase shifted several times, up to 23 ms, and combined to create a single recording for use in the simulations. An orchestra was simulated in …


Investigations Of Multi-Channel Auralization Technique For Solo Instruments And Orchestra, Michelle C Vigeant, Lily M. Wang, Jens Holger Rindel Jun 2014

Investigations Of Multi-Channel Auralization Technique For Solo Instruments And Orchestra, Michelle C Vigeant, Lily M. Wang, Jens Holger Rindel

Lily M Wang

Computer modeling of room acoustics is a useful tool in the design of acoustically sensitive spaces and an important outcome from these programs is auralizations. This study examined the perceived changes in realism and source width when listening to multi-channel auralizations compared to single channel auralizations for both solo instruments and a full orchestra. The first experiment, which examined subjective judgments of auralizations made from solo instruments, showed that perceived realism increased as the number of channels was increased from one to four to thirteen, while the relationship between source width and number of channels was less clear. In the …


Reflector Responses: A Comparison Between Odeon’S Modified Ray Tracing Algorithm And A Filtered Boundary Element Method Model, Jonathan Rathsam, Lily M. Wang, Jens Holger Rindel, Claus Lynge Christensen Jun 2014

Reflector Responses: A Comparison Between Odeon’S Modified Ray Tracing Algorithm And A Filtered Boundary Element Method Model, Jonathan Rathsam, Lily M. Wang, Jens Holger Rindel, Claus Lynge Christensen

Lily M Wang

The biggest challenge for geometrical room acoustic computer models is to capture complex wave phenomena while maintaining the low computational load of the ray tracing algorithm. Special corrections must be added to the ray tracing algorithm to account for wave phenomena such as edge diffraction, which are ignored by classical geometrical acoustics. ODEON, a well-known geometrical computer model, is in the process of upgrading its ray tracing and scattering algorithm. The new algorithm allows users to specify transmission through reflector panel arrays. To aid in the development of ODEON’s new algorithm, its predictions are compared with predictions from a boundary …


Measuring Sound Power In Ducted Heating, Ventilating, And Air-Conditioning (Hvac) Systems For Use In Verifying Acoustical Prediction Methods, Steven R. Ryherd, Lily M. Wang Jun 2014

Measuring Sound Power In Ducted Heating, Ventilating, And Air-Conditioning (Hvac) Systems For Use In Verifying Acoustical Prediction Methods, Steven R. Ryherd, Lily M. Wang

Lily M Wang

This paper discusses issues regarding in-situ methods of obtaining sound power at a point in a heating, ventilating and air-conditioning (HVAC) duct system. Such a method is being used as part of a larger investigation on acoustical prediction methods to allow for comparison of measured data to results from attenuation predictions of individual duct elements, such as elbows or dampers. Sound propagation in HVAC duct work is complex. Any measurements of sound energy in the duct must address the characteristics of sound propagation in ducts, end reflections, and air turbulence. Investigations are being conducted to understand the extents to which …


Room Acoustics Computer Modeling: Study Of The Effect Of Source Directivity On Auralizations, Michelle C Vigeant, Lily M. Wang, Jens Holger Rindel Jun 2014

Room Acoustics Computer Modeling: Study Of The Effect Of Source Directivity On Auralizations, Michelle C Vigeant, Lily M. Wang, Jens Holger Rindel

Lily M Wang

Auralizations are very useful in the design of performing arts spaces, where auralization is the process of rendering audible the sound field in a space, in such a way as to simulate the binaural listening experience at a given position in the modeled space. One of the fundamental modeling inputs to create auralizations is the source directivity. Standard methods involve inputting the measured source directivity, calculating the impulse response and convolving it with a single channel anechoic recording. An initial study was conducted using this method and the results showed significant differences in reverberation time and clarity index when using …


Objective And Subjective Evaluation Of The Use Of Directional Sound Sources In Auralizations, Lily M. Wang, Michelle C Vigeant Jun 2014

Objective And Subjective Evaluation Of The Use Of Directional Sound Sources In Auralizations, Lily M. Wang, Michelle C Vigeant

Lily M Wang

Omni-directional sources are often used in room acoustic computer simulations, as opposed to directional sources, since measured directivity data are quite limited and difficult to obtain. The purpose of this study is to investigate the objective and subjective significance of adding more complex directivity to the sources used in computer simulations and auralizations. A simple hall was used as the modelled space in the software program ODEON. Three source positions on stage and three receiver audience positions were chosen. Impulse responses (IRs) were calculated for the nine source/receiver combinations, using (a) an omni-directional source, (b) a highly directional source beaming …