Proceedings of Meetings on Acoustics [ASA 164th Meeting of the Acoustical Society of America -...

Post on 07-Apr-2017

213 views 0 download

Transcript of Proceedings of Meetings on Acoustics [ASA 164th Meeting of the Acoustical Society of America -...

Proceedings of Meetings on Acoustics

Volume 18, 2012 http://acousticalsociety.org/

164th Meeting of the Acoustical Society of America Kansas City, Missouri 22 - 26 October 2012

Session 2aAA: Architectural Acoustics

2aAA11. Source locations, listener locations, and measurement devices

Liz L. Lamour*

*Corresponding author’s address: Cavanaugh Tocci Associates, Sudbury, MA 01776, elamour@cavtocci.com

Does the location of the source affect the results of an acoustical measurement? This is the question that sparked theauthor’s Master’s Project which explores the differences between measurements taken with a source located on the stageof a performance space and a source located higher above the stage using the space’s existing sound system. Impulseresponses were gathered from four different performance halls with respect to source location, microphone location, and measurement devices used. Comparisons were made between trends in reverberation time, early decay time, and interau-ral cross-correlation coefficient. The results are not only interesting, but they also question the typical measurement prac-tices of acousticians and confirm assumptions made regarding important acoustical characteristics of performance spaces.

Published by the Acoustical Society of America through the American Institute of Physics

L. Lamour

© 2013 Acoustical Society of America [DOI: 10.1121/1.4788772]Received 9 Nov 2012; published 8 Jan 2013Proceedings of Meetings on Acoustics, Vol. 18, 015004 (2013) Page 1

Redistribution subject to ASA license or copyright; see http://acousticalsociety.org/content/terms. Download to IP: 131.230.68.4 On: Fri, 05 Dec 2014 10:02:12

Introduction For my Master of Arts in Architecture Final Project from the University of Kansas, I decided to explore the differences between measurements taken with a source located on the stage of a performance space and a source located higher above the stage using the space’s existing sound system. This project idea began last summer while I was interning with the acoustical consulting firm Cavanaugh Tocci Associates. A Principal member of the firm, Matt Moore, asked me if we could take measurements in a performance hall with the house sound system as a source or if we had to use our own loudspeaker on stage. This inquiry sparked several additional questions, including:

� Does the height of the measurement source matter? � Would there be significant changes in the results? � Which acoustical characteristics are most affected?

The above questions became the base of my graduate research. There are several reasons this research is important for acoustical consultants, architects, and owners. First, the results of this research may allow consultants to use the existing sound system in a performance hall to make quick measurements and get accurate results. Hauling less equipment to make an acoustical measurement not only saves time, but it also saves money. Another reason this research is important is that it informs consultants and their clients of potential differences in room acoustics performance based on the sound system, or a stage-based source location. Most performance halls are multipurpose and can host anything from a Broadway show to a symphony concert to a commencement ceremony. Having this understanding of how a performance hall will behave for various uses will assist consultants and clients in making educated choices about potential fixes necessary to enhance the hall.

Acoustics Basics

For this research, I focused on three room acoustics characteristics: Reverberation time, Early Decay time, and Interaural Cross-Correlation Coefficient. These three are considered to be among the most important acoustical characteristics of a performance hall. Reverberation time (RT60) is “the amount of time it takes for sound to decay to inaudibility or 60 dB below the level of initial sound after the source has stopped.1” Reverberation time is often mistaken as “echo.” It can provide the feeling of warmth and fullness in a performance hall. For my acoustical measurements, RT20 was used instead of RT60 due to the ambient noise levels of the performance halls. RT20 is a decay of 20 dB, and it is assumed that the decay continues at the same rate to 60 dB of total decay. Full reverberation time is calculated from RT20 by multiplying RT20 by 3 to represent the full 60 dB of decay. For the majority of my measurements I used approximately -5 dB

L. Lamour

Proceedings of Meetings on Acoustics, Vol. 18, 015004 (2013) Page 2

Redistribution subject to ASA license or copyright; see http://acousticalsociety.org/content/terms. Download to IP: 131.230.68.4 On: Fri, 05 Dec 2014 10:02:12

�������������� ������������������������������ �������������������������������� ����������!����!��� �������� �������"����������#���� ���$�����������%� &����'�����"��� �������������

������������ �������� ���� ������� ������������������������� ���������������� !"#$!"�� ���!""�

�� (���!�)��!��� ���()������*������ ����+ �����'�������'�����������'����!�,������������������'����������� ����'���������� ����������&&����(���!����!��� ������������ �������� ���'���� ��� ����'����������������� ����-��������� �������� ������!������������������!����!��� ������� ����� ����� ��� ����'���������� �������� ���!��������������������������� ��(���!����!��� ���� �������������������&������������������������������� ��������� "����� ����.�����.�����������.��''�������"/..�������* ��� �� �����'����������������''�������������������� �������������������������'������������������'�������������,�"/..�������������������'��������'�������& ���#��������'��������'�������� ��� ������!��� ����"������������ ��� ����'��&��� �������/�����������''�������������������� ���������������������'����������������������������������"/..��"/..������&��������������� �������������������#��������� ������� �������������������������� ������ /��&����� ��!�������#������������� ���������������� �����!����!��� �������������� ��� ����'��������������������� ���������������������� ���0����� ��� ���������� ���'�������' ���1�����'����!��� ����+ �����'������������������� �� ��� �� ��������������&����������������!��������� �!#�������������2�����������!���������!�&��������'�������������������������"������'������'�&�!���� ����#�������� ���������������������&��������� ��#�����������'� ��3���� ������%&�������!���������!�&��������'���������������� ����� &����������������' ��#���������!��'��� ����������� ���� �����������������!&����'� ��3����������''��������������4�

L. Lamour

Proceedings of Meetings on Acoustics, Vol. 18, 015004 (2013) Page 3

Redistribution subject to ASA license or copyright; see http://acousticalsociety.org/content/terms. Download to IP: 131.230.68.4 On: Fri, 05 Dec 2014 10:02:12

� Simultaneous masking occurs when two sound signals are playing at the same time.

� Forward masking occurs when a first sound masks a second sound occurring closely after the first sound ends.

� Backwards masking occurs when a second sound occurring closely after a first sound masks the first sound.

Simultaneous masking behaves exactly as it is described, while a more in depth explanation is needed to understand how forward masking works. For every sound signal, there is a large spike in our hearing at the onset of the sound, which levels off as the sound continues to be played. When the sound signal is stopped, the levels of our hearing decrease below our normal hearing levels into a short recovery period before gradually rising up to our normal hearing levels. This process is better visualized when viewing a PST histogram, such as the one below (Figure 2.)

Figure 2: PST Histogram, inserted from notes taken during the class SPLH 663 Spring 2011

Measurement Devices and Locations

For my research, I used two different types of microphones. To measure reverberation time and early decay time I used an Omni-Directional Measurement Microphone, and for IACC I used a Stereo Ambient Sampling System Microphone (SASS.)

L. Lamour

Proceedings of Meetings on Acoustics, Vol. 18, 015004 (2013) Page 4

Redistribution subject to ASA license or copyright; see http://acousticalsociety.org/content/terms. Download to IP: 131.230.68.4 On: Fri, 05 Dec 2014 10:02:12

Figure 3: Omni-Directional Measurement Microphone and SASS

Typically a “dummy head” microphone is used for IACC measurements, however, the SASS microphone is similar. The purpose of using a different microphone to calculate IACC is to simulate the human experience of hearing sound as closely as possible. The dummy head microphone is just that, a dummy head with a microphone in each ear to capture sound. SASS does not look like a human head, but is designed to perform the same task. It has a “nose” in front and “ears” on the sides to act as a human head without being exactly shaped like one. Two pressure zone microphones (PZM) capture sound at each “ear” location while the “nose” buffers, blocks, and/or move the sound the way the front of our head would. Bob Coffeen, a professor and my advisor at the University of Kansas, performed comparison measurements with both a dummy head microphone and our SASS and found similar results between the two. Therefore, the price advantage and smaller size of the SASS microphone makes it ideal for measurement-making college students. In addition to the two microphones, I also used two different types of loudspeakers. I used our Omni-Directional Dodecahedron loudspeaker for the on-stage source measurements, and the existing house loudspeaker system unique to each hall I measured. Several differences can be pointed out immediately regarding the construction of each loudspeaker situation. The dodec is 12-sided and contains a loudspeaker on each side. The loudspeakers used in the dodec are small and have a 4-inch diameter diaphragm. Loudspeakers used for house systems in performance halls are large and often contain more than one type of loudspeaker component.

L. Lamour

Proceedings of Meetings on Acoustics, Vol. 18, 015004 (2013) Page 5

Redistribution subject to ASA license or copyright; see http://acousticalsociety.org/content/terms. Download to IP: 131.230.68.4 On: Fri, 05 Dec 2014 10:02:12

(a) (b)

Figure 4: The KU dodecahedron loudspeaker (a) and an example of larger house system loudspeakers(b), latter photo courtesy of Matt Moore

In each hall I measured, I used three different microphone positions: center, off center, and one towards the rear of the hall closer to a wall.

Figure 5: Examples of microphone locations in each hall I measured

The location of the dodec loudspeaker on stage was always just a little off center and towards the front of the stage. The house sound system locations differed for each hall. At Yardley Hall in Johnson County Community College’s Carlsen Center, the house loudspeakers are located on the sides of the stage near the top of the proscenium. Also at JCCC, Polsky Theater’s house loudspeakers are located on the sides of a lighting platform above the thrust stage and also directly on the sides of the stage. For both the Lied Center at University of Kansas and Topeka Performing Arts Center, the house loudspeakers are located in a central cluster hidden above the top of the proscenium.

L. Lamour

Proceedings of Meetings on Acoustics, Vol. 18, 015004 (2013) Page 6

Redistribution subject to ASA license or copyright; see http://acousticalsociety.org/content/terms. Download to IP: 131.230.68.4 On: Fri, 05 Dec 2014 10:02:12

Figure 6: House sound system locations for each hall I measured. Top left photo courtesy of Bob Coffeen,

bottom right photo produced by Topeka Performing Art Center and courierpress.com (www.courierpress.com/photos/galleries/2011/feb/07/topeka-venues/)

Measurement Analysis

I utilized the program EASERA for creating impulse responses to analyze.

Figure 7: Impulse response from EASERA

Instead of taking results directly from EASERA, I analyzed the Schroeder integration for individual one-third octave bands.

L. Lamour

Proceedings of Meetings on Acoustics, Vol. 18, 015004 (2013) Page 7

Redistribution subject to ASA license or copyright; see http://acousticalsociety.org/content/terms. Download to IP: 131.230.68.4 On: Fri, 05 Dec 2014 10:02:12

Figure 8: Schroeder calculation third-octave frequency band impulse response in EASERA

For each individual third-octave frequency band, I set a “line of best fit” to determine the reverberation time and early decay time for that band.

Figure 9: Creating a “line of best fit” over Schroeder calculation third-octave impulse response in

EASERA This was decided to be the best route due to inconsistencies in EASERA’s direct results. The issues were partially due to the Noise Compensation option, which assumes an unspecified noise floor for the measurement and chops off the signal when it assumes the signal has reached that noise floor.

Time (S) is the horizontal axis and sound pressure level (dB)

is the vertical axis

Time (S) is the horizontal axis and sound pressure level (dB)

is the vertical axis

L. Lamour

Proceedings of Meetings on Acoustics, Vol. 18, 015004 (2013) Page 8

Redistribution subject to ASA license or copyright; see http://acousticalsociety.org/content/terms. Download to IP: 131.230.68.4 On: Fri, 05 Dec 2014 10:02:12

Figure 10: The left image shows noise compensation ON, the right image shows noise compensation OFF

I ultimately decided to turn that feature off and look at the entire Schroeder curve, set limits to get about RT20, and make my own result analysis. The graph below illustrates the reasons behind that decision (Figure 11.)

Figure 11: My Schroeder “line of best fit” measurements (green) vs. EASERA’s noise compensation

options The graph above also shows another issue I encountered, especially with measurements involving the dodec loudspeaker. I could not get enough signal in the lower frequencies to get accurate results from EASERA (notice on Figure 11 that the issues reside below 500 Hz) and had a difficult time extracting my own results.

Time (S) is the horizontal axis and sound pressure level (dB)

is the vertical axis

L. Lamour

Proceedings of Meetings on Acoustics, Vol. 18, 015004 (2013) Page 9

Redistribution subject to ASA license or copyright; see http://acousticalsociety.org/content/terms. Download to IP: 131.230.68.4 On: Fri, 05 Dec 2014 10:02:12

��������!�%��� ������������� �����������%������������������&����'� ��� ��������������(�����&�����'�

�"���������� �����������������'��+ ��!�������������������'��������� ����!��� ��� ��&��3���������������� ��#�+ ������ &�!#����!�������������������&��� ������������'��+ ��!������������������������� ��&��3��#������������������#������ ������ ��&��3��������������&��� ��������������������������+ ������������������'��+ �����#���������������������'�������52�����&&��%� ����!����'����������0���������� ��&��3���������&��� ����� ''������� � ����'�����������'��+ �����#������ & �������&������'���������'��+ ������� ''������%� &��������� ����6����

��������)�����* �������� �����+���������,����-����(������.��� /�����-����(�+ ��������%����

��

����������� �����

� ����'������'�����'� �������� ���������'��������"����3� ��� �� �����������7�����!�5�������8�������.� ��!�.� ���!�.����������

���-����(�&�0'������������0��� �� *��� ��������������������/���&�1'��������

/����� �� *���

�����&%'������������0��� �� *��� ��������������������/���&�1'�

�������/����� �� *���

L. Lamour

Proceedings of Meetings on Acoustics, Vol. 18, 015004 (2013) Page 10

Redistribution subject to ASA license or copyright; see http://acousticalsociety.org/content/terms. Download to IP: 131.230.68.4 On: Fri, 05 Dec 2014 10:02:12

Figure 14: Yardley Hall, Johnson County Community College, Overland Park, KS. Bottom left photo

produced by Johnson County Community College (www.jccc.edu/performing-arts-series/yardley-hall.html) The hall has approximately 1300 upholstered seats and features manual variable acoustics along the sidewalls. Diffusive, dampened, wooden, pyramidal shapes can be exposed when a longer reverberation time is desired, or covered up by heavy drapery for a shorter reverberation time. Graphs of measurements taken at Yardley Hall are located in figures 19-23. Polsky Hall is also located at JCCC.

Figure 15: Polsky Theater, Johnson County Community College, Overland Park, KS

It was designed as a space exclusively for drama and speech performance. Polsky is the driest of the four halls I surveyed, meaning it has the lowest average mid-frequency reverberation time. There are large pyramidal shapes that jut out of the sidewalls, which add some diffusion. The idea of a pyramidal shape also mirrors the design in Yardley Hall. Graphs of measurements taken at Polsky Hall are located in figures 24-28. The Lied Center is located on the campus of University of Kansas.

L. Lamour

Proceedings of Meetings on Acoustics, Vol. 18, 015004 (2013) Page 11

Redistribution subject to ASA license or copyright; see http://acousticalsociety.org/content/terms. Download to IP: 131.230.68.4 On: Fri, 05 Dec 2014 10:02:12

Figure 16: Lied Center, University of Kansas, Lawrence, KS

It has approximately 2000 upholstered seats. Lied Center was built to have variable acoustics in the hall, however the mechanism was damaged and has not been used recently. The variable acoustics allowed curtains to be deployed behind grills in the sidewalls of the audience seating area when a shorter reverberation time was desired. Graphs of measurements taken at the Lied Center are located in figures 29-33. Topeka Performing Arts Center is the largest hall I measured for my research.

Figure 17: Topeka Performing Arts Center, Topeka, KS. Bottom right photo produced by Leah Sewell of

seveneightfive magazine (www.seveneightfive.com/arts-entertainment/tpacs-capacity/) There are approximately 2600 upholstered seats and it was renovated in the Art Deco style. Ceiling “cloud” reflectors reflect sound energy back into the audience area of the hall and help those on stage project into the hall. In addition to comparing the dodec to the house loudspeaker system at TPAC, I also used a combination of the house loudspeakers plus satellite loudspeakers located above the audience area as a comparison. TPAC Dodec v. House System v. House System + Satellite Loudspeakers A comparison between the three source location scenarios used at TPAC revealed that the dodec loudspeaker location is most similar to the house loudspeaker location with the addition of the satellite loudspeakers.

L. Lamour

Proceedings of Meetings on Acoustics, Vol. 18, 015004 (2013) Page 12

Redistribution subject to ASA license or copyright; see http://acousticalsociety.org/content/terms. Download to IP: 131.230.68.4 On: Fri, 05 Dec 2014 10:02:12

��������2��������� �������� �������� ��(���� (��������������+��,��������������������� �����(����������

� ��������������� ��������+�� �����,����������������� ���� ���������������� �����(������9����&������%&���������'��������� ����������������������������� ��&��3������������� ����� ��&��3����!��� �&� �������������� ��&��3��������������������������'����������������� ��&��3�����������������������������!���������� ����� ��&��3����!��� #�����������!����&������������������������� ��������������&��������'������������ ��&��3����:��&���'��� ��� �� �������3��������&�3��9��'�� ����/����.��������������������'�� ����6;�6$���

"��������������� &�������� ������&���� ����������������������� ���!#�"������� &���������������������������!��� �����������������4�<����.������������&�3��9��'�� ����/����.�������������� ������������������������� ����#��������&���� &������������������������������������� ���;����

��������������

��/��+�� ������������ "���������#������������ ��&��3������&��!���������!������������������������ ����� ��������������� ����� ��&��3����!��� ��������''������������������������������������6��������������������������� ��&��3��������� ����� ��&��3����!��� ��=����&��&����������������� &�����������'�����������''���������������� ���#����������� ���������������� �������������� ����� ��&��3����!��� �� ������ ����'��������������������� �� ��� �� ������'��������!��5������#�"��� ������!���� ��������� ���������� &��������&&������'����!������������������������&�����������������������������&��'�� ������������������� ��� �� ������������������ �����=��!��� ���������������� ��&���������������'����������������������+ �& ���#���������� �������������'�������� ���������> ��������������������+ �& �������������'� �������������!��� ���������������������&������������������ �� ����� &��������'����������������� �� ��� �� ������������� ���&���������������������������������������&��������"������������ ����'�� �������� �����'�����&�����������������������������������������������!����'���������� ����������#������ ���������������������� �����&�����!��������������'��+ ��������/�����������'��������� ���&�����

L. Lamour

Proceedings of Meetings on Acoustics, Vol. 18, 015004 (2013) Page 13

Redistribution subject to ASA license or copyright; see http://acousticalsociety.org/content/terms. Download to IP: 131.230.68.4 On: Fri, 05 Dec 2014 10:02:12

positions will most likely yield the most accurate results when measuring reverberation time in a room because it gives the consultant and the client a better feel for the entire room and not just one location. Early Decay Time Consistently, the dodec loudspeaker location displayed higher early decay time results than the house system. Sometimes that difference, especially in the mid-to-upper frequencies, is up to half a second. One reason why there is a more drastic variation between source locations with early decay time than with reverberation time is that when measuring early decay time, the sound has less time to reflect around the room boundaries. Early decay time is essentially the direct sound at the listener location with minimum room influence. With that in mind, the dodec loudspeaker location was approximately at or just below ear level for a majority of the audience and projected approximately omni-directionally all around the hall. The house loudspeaker system, on the other hand, was directional and was aimed at the chairs and people in the hall, which then absorbed the sound energy more quickly. Similar to the reverberation time results, I could not find a consistent pattern between microphone location and early decay time. However, there is more variance between microphone locations when compared with the reverberation time results, and all of the microphone location results for early decay time follow a similar trend. The largest variations occur in the lower frequencies, but that could be attributed to the differences in low-frequency response between the source loudspeakers. An average of several microphone positions will produce the most accurate results for the whole room when measuring early decay time. Interaural Cross-Correlation Coefficient With the exception of Polsky Theater (the least reverberant of the four halls surveyed), the dodec loudspeaker location produced the best IACC results. This could be the result of the dodec loudspeaker being closer to the seating area and ear height of the audience, producing more lateral reflections. Lateral reflections aid in creating a larger difference between sounds heard by the left and right hear, hence resulting in a better feeling of envelopment and spaciousness. IACC results are highest at the center microphone location. The center microphone location in each hall is located in the approximate center of the seating area. The IACC is highest, or not as good, in the center of the seating area most likely because it is farther away from the walls and thus receives less lateral reflections than other microphone locations that are closer to the walls. In addition, if the hall is symmetrical the reflections arriving at both ears are nearly the same. Another interesting result is that the house loudspeaker system had better IACC results only at the center microphone position. Perhaps the higher angle of the house loudspeakers allows better ceiling reflections than lateral reflections at the center microphone location, which would explain why a more elevated source only performs better in the center of the hall. A chart

L. Lamour

Proceedings of Meetings on Acoustics, Vol. 18, 015004 (2013) Page 14

Redistribution subject to ASA license or copyright; see http://acousticalsociety.org/content/terms. Download to IP: 131.230.68.4 On: Fri, 05 Dec 2014 10:02:12

� &������"/..��������������� ����!��� ����������������������������'� ��������� ���;����

����������� )��������������������%���?�"���������������#�"�������������3�"��� ���'������!���'����������� �����(�������������"@ ��� ��������������'�� �������������������&�������#���@����''� ������&������������%����������������!&���'� ��� �� ��������� ������ �3������������+ �& ���� ������� �3������� ��� �� �������� &�����!���&��������������������� ������ ���������������������������� ���� ���?�5��������������������������&���������������������� �����?�0��������������������� ��� �� ���������������� ������ ����������'!?���� "������!#��������������&��������> ������ ��!�+ ����������������������������/���� �����#�� �������� �����#�������&�������� ������#�"�3�������������������������������'���&��'�� ��������#������������������&��>��������������������� ���3����������"�� ���'��������� ������������������!������������������!��������� �����������'������� ���������������� ����������������������#������������������3������������������������������!���������@�� ������������������ ��������� ���������� �������� ������������ ��������!������������'� �����"��������������������������� ���������������� �������������������&��� ������������'��������'�������& ���������&��� �����#�� ��'��� ��!������������ ����2��������#� ����������������� ����� ������������������ ����� &��'���� ����������#�������'���������'��&���������� ��������� �������� ������ /��"������� !�&��'�����������'������� ����#�"�� �������������������� ��������%&��� ���������������������������''����������������� ����������#� ���&������������#����� ��� �� ������������"�� ������ ��� ����� �������������������������!���������������������������!������&��'�� ������������ ��������������������� ���� ����%&�������� �������#����������������������%���?�=!������������������&������!������A �� ��� �� �����������3�������� �������������������!�������������!2���� ��������!��� ������������������������������#����������������!#���������!�������� ��@������������� �����!��!��� �' ������������ ����!������������'���3������ ������ ��� �� ��������������� &�����&����������� ����%&��������'��� ��������&���� �����&������'������'�����������!���������B���������������!��������"������� ����������� ���� �����!��!��� ����3�#�"�� ��� &����������������������������'���������!����!��� ��������������� ��� ����'��������������� ������������������������������!#�� ��'�������������������"������&���������������������'�������� !�&�������������� �����������'�������&�������'���������

L. Lamour

Proceedings of Meetings on Acoustics, Vol. 18, 015004 (2013) Page 15

Redistribution subject to ASA license or copyright; see http://acousticalsociety.org/content/terms. Download to IP: 131.230.68.4 On: Fri, 05 Dec 2014 10:02:12

Floor Plans for Microphone Positions, RT and EDT Graphs, Comparison

Yardley Hall

Figure 19: Yardley Hall floor plan Figure 20: Reverberation time (a) and early decay time (b), dodec vs. house system inYardley Hall

(a) (b)

Figure 21: Reverberation time at each microphone position, dodec (a) and house system (b) in Yardley Hall

(a) (b)

Figure 22: Early decay time at each microphone position, dodec (a) and house system (b) in Yardley Hall

(a) (b)

DodecHouse

DodecHouse

CenterRear Off CenterFront Off Center

CenterRear Off CenterFront Off Center

CenterRear Off CenterFront Off Center

CenterRear Off CenterFront Off Center

Center

Rear Off Center

Front Off Center

Center

Rear Off Center

Front Off Center

Figure 23: Early decay time (a) vs. reverberation time (b) at each microphone position, dodec in Yardley Hall(a) (b)

L. Lamour

Proceedings of Meetings on Acoustics, Vol. 18, 015004 (2013) Page 16

Redistribution subject to ASA license or copyright; see http://acousticalsociety.org/content/terms. Download to IP: 131.230.68.4 On: Fri, 05 Dec 2014 10:02:12

Polsky Theater

Figure 24: Polsky Theater floor plan Figure 25: Reverberation time (a) and early decay time (b), dodec vs. house system inPolsky Theater

(a) (b)

Figure 26: Reverberation time at each microphone position, dodec (a) and house system (b) in Polsky Theater

(a) (b)

Figure 27: Early decay time at each microphone position, dodec (a) and house system (b) in Polsky Theater

(a) (b)

DodecHouse

DodecHouse

CenterRear WallRear Off Center

CenterRear WallRear Off Center

CenterRear WallRear Off Center

CenterRear WallRear Off Center

Center

Rear Wall

Rear Off Center

Center

Rear Wall

Rear Off Center

Figure 28: Early decay time (a) vs. reverberation time (b) at each microphone position, dodec in Polsky Theater(a) (b)

L. Lamour

Proceedings of Meetings on Acoustics, Vol. 18, 015004 (2013) Page 17

Redistribution subject to ASA license or copyright; see http://acousticalsociety.org/content/terms. Download to IP: 131.230.68.4 On: Fri, 05 Dec 2014 10:02:12

Lied Center

Figure 29: Lied Center floor plan Figure 30: Reverberation time (a) and early decay time (b), dodec vs. house systemin the Lied Center

(a) (b)

Figure 31: Reverberation time at each microphone position, dodec (a) and house system (b) in the Lied Center(a) (b)

Figure 32: Early decay time at each microphone position, dodec (a) and house system (b) in the Lied Center(a) (b)

Figure 33: Early decay time (a) vs. reverberation time (b) at each microphone position, dodec in the Lied Center

DodecHouse

DodecHouse

CenterRear WallRear Off Center

CenterRear WallRear Off Center

CenterRear WallRear Off Center

CenterRear WallRear Off Center

Center

Rear Wall

Rear Off Center

Center

Rear Wall

Rear Off Center

(a) (b)

L. Lamour

Proceedings of Meetings on Acoustics, Vol. 18, 015004 (2013) Page 18

Redistribution subject to ASA license or copyright; see http://acousticalsociety.org/content/terms. Download to IP: 131.230.68.4 On: Fri, 05 Dec 2014 10:02:12

Topeka Performing Arts Center

Figure 34: TPAC floor planFigure 35: Reverberation time (a) and early decay time (b), dodec vs. house system vs.house system plus satellite loudspeakers in TPAC

(a) (b)

Figure 36: Reverberation time at each microphone position, dodec (a), house system (b), and house system plus satelliteloudspeakers (c) in TPAC

(a) (b) (c)

Figure 37: Early decay time at each microphone position, dodec (a), house system (b), and house system plus satellite loudspeakers(c) in TPAC

(a) (b) (c)

Figure 38: Early decay time (a) vs. reverberation time (b) at each microphone position, dodec in TPAC

DodecHouseHouse +Satellites

DodecHouseHouse +Satellites

Off CenterRear CornerCenter

Off CenterRear CornerCenter

Off CenterRear CornerCenter

Off CenterRear CornerCenter

Off CenterRear CornerCenter

Off CenterRear CornerCenter

Off Center

Rear Corner

Center

Off Center

Rear Corner

Center

(a) (b)

L. Lamour

Proceedings of Meetings on Acoustics, Vol. 18, 015004 (2013) Page 19

Redistribution subject to ASA license or copyright; see http://acousticalsociety.org/content/terms. Download to IP: 131.230.68.4 On: Fri, 05 Dec 2014 10:02:12

Figure 39: Reverberation time (a) and early decay time (b), comparing the satellite loudspeaker addition to the dodec andhouse system scenarios in TPAC

(a) (b)

Lied Center vs. TPAC

Figure 40: Reverberation time (a) and early decay time (b), Lied Center vs. TPAC(a) (b)

Dodec

House +Satellites

Dodec

House +Satellites

House

House +Satellites

House

House +Satellites

Dodec vs. Satellites Dodec vs. SatellitesHouse vs. Satellites House vs. Satellites

Dodec

House

House +Satellites

Dodec

House

House +Satellites

DodecHouse Dodec

House

Lied Center Lied CenterTPAC TPAC

L. Lamour

Proceedings of Meetings on Acoustics, Vol. 18, 015004 (2013) Page 20

Redistribution subject to ASA license or copyright; see http://acousticalsociety.org/content/terms. Download to IP: 131.230.68.4 On: Fri, 05 Dec 2014 10:02:12

Interaural Cross-Correlation Coeffienct

Yardley Hall

Dodec House Dodec House Dodec House

Lied Center

Dodec House Dodec House Dodec House

Polsky

Dodec House Dodec House Dodec House

TPAC

Dodec House Dodec House Dodec House

0.6 0.8 0.2 0.6 0.4 0.9

0.7 0.6 0.5 0.6 0.6 0.7

0.6 0.5 0.6 0.4 0.5 0.5

0.6 0.4 0.5 0.8 0.4 0.8

Center Rear Wall Rear Off Center

Off Center Rear Corner Center

Center Rear Off Center Front Off Center

Center Rear Wall Rear Off Center

Figure 41: IACC results from the four halls

L. Lamour

Proceedings of Meetings on Acoustics, Vol. 18, 015004 (2013) Page 21

Redistribution subject to ASA license or copyright; see http://acousticalsociety.org/content/terms. Download to IP: 131.230.68.4 On: Fri, 05 Dec 2014 10:02:12

Bibliography

1. W. J. Cavanaugh, G. C. Tocci, and J. A. Wilkes, Architectural Acoustics Principles And Practice, 2nd edtion (John Wiley & Sons, Inc, Hoboken, New Jersey, 2010), pp. 209-240.

Notes and knowledge from Bob Coffeen’s classes at the University of Kansas: Arch 720, Arch 721, Arch 600, Arch 700, Studio, Fall 2010-Spring 2012 Notes and knowledge from Tiffany Johnson’s SPLH 663 class at the University of Kansas, Spring 2011.

Thank you to those who offered assistance and advice with this research:

Bob Coffeen, University of KansasBen Bridgewater, University of KansasRobert Healey, University of Kansas

Bob Coffeen's Acoustics Studio, Spring 2012Matt Moore, Cavanaugh Tocci Associates

Rick Talaske, The Talaske GroupAnn and Andy Hause, Lied Center of Kansas

Technical Crew at Johnson County Community CollegeTechnical Crew at Topeka Performing Arts Center

L. Lamour

Proceedings of Meetings on Acoustics, Vol. 18, 015004 (2013) Page 22

Redistribution subject to ASA license or copyright; see http://acousticalsociety.org/content/terms. Download to IP: 131.230.68.4 On: Fri, 05 Dec 2014 10:02:12