2aED16. Animations, visualizations, and auralizations in architectural acoustics. Session: Wednesday Morning, Nov 29 Author: Ralph T. Muehleisen Location: Civil and Architectural Eng., Illinois Inst. of Technol., Chicago, IL 60616,
[email protected]
Abstract: A number of animations, visualizations, and auralizations developed for use in architectural acoustics classes are presented. Animations of plane waves, spherical waves, and standing waves were created using MATLAB software. Visualizations of modes in regular and arbitrary shaped enclosures were created in Comsol Multiphysics software. Auralizations of tonal and broadband noise, hearing loss, transmission loss, and classroom acoustics were created using Adobe Audition software.
These animations, visualizations, and auralizations have been collected in a web interface. The size of some audio and animation files precludes convienient browsing over the internet. Additionally, copyright restrictions only allow limited presentation of some auralizations for educational purpose. Thus, you must contact the author in order to download the web pages or obtain a CD with the web pages on it. The following PDF capture of the web page gives a feel of the web site. It should be noted that Adobe acrobat did not properly render the web pages, although both Firefox and Internet Explorer do render the pages properly. The audio files are not embedded in the PDF and the animations only show as a single static frame of the animation.
HomeDiffractionWavesRoom ModesReverb TimeTransmissionNoiseClassroom Hearing Loss
Animations, Auralization and Visualizations in Acoustics Diffraction
Animations and Visualizations
Simple Waves Room Modes
Reverberation Time
Auralizations
Transmission Loss and Speech Privacy Classroom Acoustics Hearing Loss
Some of the auralizations included here utilize copyrighted content which is used for educational purposes under Section 107 of the Copyright Act. As a result, this work has limited distribution and uncontrolled public access of those portions which include such copyrighted content is not allowed. These animations, auralizations, and visualizations are © 2006 by Ralph T. Muehleisen and are licenced under a Creative Commons Attribution-NonCommercial 2.5 License.
HomeDiffractionWavesRoom ModesReverb TimeTransmissionNoiseClassroom Hearing Loss
Animation of Diffraction over a Barrier The following visualizations show how diffraction over a barrier varies with the ratio of barrier height to wavelength. Shown are steady state plots of sound level as well as a transient animation showing the diffraction of sound over the barrier.
Click a plot below to see the animation or a larger plot of the steady state response.
Barrier Height
h=λ
h=2λ
Transient Animation
Steady State Lp
h=4λ
The visualizations were created using COMSOL Multiphysics with the Acoustics Module. A transient solution was computed to show the initial diffraction of sound over the barrier. A steady state solution was computed to map out the steady state sound levels throughout the computation region. Mesh details for the computational model can be found in the reports generated by COMSOL. Click the buttons below to view the reports.
COMSOL Reports Transient
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h=λ
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h=2λ
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h=4λ
Steady State
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h=λ
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h=2λ
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h=4λ
These animations, auralizations, and visualizations are © 2006 by Ralph T. Muehleisen and are licenced under a Creative Commons Attribution-NonCommercial 2.5 License.
HomeDiffractionWavesRoom ModesReverb TimeTransmissionNoiseClassroom Hearing Loss
Simple Wave Animations Click on a figure below to see the animation and a short description. If you do not see any animation, check your web browser: On IE7 select Tools -> Internet Options -> Advanced -> Multimedia -> Play Animations in Web Pages On Firefox go to URL "about:config" and set "image.animation_mode" to "normal"
Traveling Plane Wave
Simple Spherical Wave
Superposition
Standing Wave
These animations were generated using MATLAB and saved as AVI files. The AVI files were converted to animated GIF files using the Ulead Gif Animator software. The MATLAB code is original, but based upon Mathematica animations developed by Dan Russell and Vic Sparrow.
These animations, auralizations, and visualizations are © 2006 by Ralph T. Muehleisen and are licenced under a Creative Commons Attribution-NonCommercial 2.5 License.
HomeDiffractionWavesRoom ModesReverb TimeTransmissionNoiseClassroom Hearing Loss
Modes in Hard Walled Rooms The following plots show the first five modes for several room shapes. First shown is a simple rectangular room with a 10 m x 6m profile. The second set of plots shows the same room with one wall splayed. The third and fourth sets of plots shows the room with two splayed walls. A fifth set of plots shows a room of approximately the same size but of a completely amorphous shape. One of the important things to note is that splaying the walls has little effect on the modal structure of the room. The resonance frequencies and mode shapes change little when the walls are angled to eliminate parallel surfaces. Modes are not eliminated, they are just harder to compute. Hopefully these plots will help reinforce the idea that all rooms have modes and that those modal shapes and frequencies are dominated by the general dimensions of the room. Click the Mode Shape Below to see a larger plot or click the button on the left to see the COMSOL report for that room shape.
Room Shape
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Mode 1
Mode 2
Mode 3
Mode 4
Mode 5
17.2 Hz
28.6 Hz
33.3 Hz
34.3 Hz
44.6 Hz
17.1 Hz
28.3 Hz
33.4 Hz
34.6 Hz
44.7 Hz
Rectangular
1 Side Splayed
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Side+End Splay 17.1 Hz
28.1 Hz
33.4 Hz
34.5 Hz
44.7
17.2 Hz
27.4 Hz
34.3 Hz
45.1 Hz
51.3 Hz
14.6 Hz
20.3 Hz
27.5 Hz
30.3 Hz
38.0 Hz
2 Sides Splayed
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Amorphous
These animations, auralizations, and visualizations are © 2006 by Ralph T. Muehleisen and are licenced under a Creative Commons Attribution-NonCommercial 2.5 License.
HomeDiffractionWavesRoom ModesReverb TimeTransmissionNoiseClassroomHearing Loss
Effects of Reverberation on Voice and Music This page is designed to show you how a room affects the sound of voice and music. Below you will find a number of different music and speech samples as they would sound in different environments. For example, to compare speech in several room environments you would click on the links in the row labeled Speech.
Warning! The samples are in a .wav format which results in some large file sizes that may take a few moments to load.
Anechoic Room
Speech
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Classroom
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Cello
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Orchestral ●
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Speech
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Guitar
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Organ
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Cello
Organ Duck
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Cathedral
Speech
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Guitar
Orchestral ●
Duck
Concert Hall
Guitar
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Cello
Orchestral Organ Duck
Descriptions of the Different Rooms Anechoic RoomClassroomConcert HallCathedral
Description of the Different Sounds SpeechGuitarCelloOrchestralOrganDuck
The auralizations on this page include some copyrighted content which is used for
Speech
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Guitar Cello
Orchestral ●
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Organ Duck
educational purposes under Section 107 of the Copyright Act. As a result, this page has limited distribution and uncontrolled public access of those portions which include copyrighted content is not allowed.
These animations, auralizations, and visualizations are © 2006 by Ralph T. Muehleisen and are licenced under a Creative Commons Attribution-NonCommercial 2.5 License.
HomeDiffractionWavesRoom ModesReverb TimeTransmissionNoiseClassroom Hearing Loss
Transmission Loss and Speech Privacy Auralizations The following auralizations were developed to show the effects of different types of wall construction on sound transmission.
Outdoor to Indoor Noise Transmission This first auralization shows the effects of window and wall construction on urban traffic noise. The sound clips are all auralizations of the interior noise after transmission. To aid in the comparison, all the interior sound levels have been raised by 20 dB. Click on the button to hear the sound.
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Through STC 35
Standard Insulating Glass Unit 1/4" Glass -1/2" Air Space -1/4" Glass
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Through STC 48
High STC Laminated Insulating Glass unit 1/4" Laminated Glass - 1/2" Air Space - 3/8" Glass
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Through STC 61
Standard CMU Exterior Wall 6" CMU Block - 2-1/2 Metal Studs w/ insulation - 5/8" Gypsum
Speech Privacy This second auralization shows the effects of wall construction on speech privacy from a courtroom. The first clip is the sound in the courtroom itself and the other clips are the sound in an adjacent rooms with different wall constructions. Click on the button to hear the sound.
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In Courtroom
Through STC 37
Sound as heard in the courtroom itself
Standard Interior Wood Stud Wall 5/8" Gypsum - 3.5" Wood Studs with no Insulation - 5/8" Gypsum
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Through STC 49
Quiet Interior Wall 5/8" Gypsum - 3.5" Metal Studs + Insulation - 5/8" Gypsum
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Through STC 62
High STC Interior Wall 1.25" Gypsum - 6" Metal Studs + Insulation - 1.25" Gypsum
These auralizations were created using transmission loss data for the different wall and window contructions taken from the text "Architectural Acoustics - Principles and Design" by Madan Mehta. The 16 bit source wav files were filtered in Adobe Audition V1.5 with the scientific filters option using TL data from the textbook. The sound clip used for the courtroom speech privacy auralization comes from the movie "To Kill A Mockingbird" and is copyrighted. It is used here for educational purposes under Section 107 of the Copyright Act. As a result, this page has limited distribution and uncontrolled public access of those portions which include copyrighted content is not allowed.
These animations, auralizations, and visualizations are © 2006 by Ralph T. Muehleisen and are licenced under a Creative Commons Attribution-NonCommercial 2.5 License.
HomeDiffractionWavesRoom ModesReverb TimeTransmissionNoiseClassroom Hearing Loss
Noise and Tone Demos Below are two sounds with the same octave band spectra, but differing 1/3 octave and narrowband spectra. This shows how comparing sounds by their octave band spectra can be deceiving
Click the figures below to hear the sound that created each spectrum
Pink Noise Spectra
Tonal Noise Spectra
Below are three types of noise: white, pink, and brown. Click on the noise name to hear a sample of the noise
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White Noise
White noise has a flat narrowband spectrum but a octave and 1/3 octave band spectrum that rises 3 dB/octave. This sounds quite hissy
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Pink Noise
Pink noise (aka 1/f noise) has a narroband spectrum that drops 3 dB/octave and a flat octave and 1/3 octave band spectrum. This has less hiss and more roary.
Brown noise (aka 1/f2 noise) has a narrowband spectrum that drops by 6 dB/octave and an band spectrum that drops at 3 dB/oct. This is very roary. Because of the low frequency ●
Brown Noise
content it sounds quieter than the white and pink noise despite being of higher maximum amplitude.
These noises and plots were created using MATLAB. Random noise was generated to create the white noise source and the white noise was filtered to obtain pink and brown noise. The 1/3 and octave band spectra were obtained using the octave filter toolbox available from the MATLAB File Exchange
These animations, auralizations, and visualizations are © 2006 by Ralph T. Muehleisen and are licenced under a Creative Commons Attribution-NonCommercial 2.5 License.
HomeDiffractionWavesRoom ModesReverb TimeTransmissionNoiseClassroom Hearing Loss
Classroom Acoustics Auralization The following auralization was developed to show the effects of noise and reverberation on speech intelligibility in classrooms. In the auralizations, background HVAC noise at an appropriate level was added to a reverberant speech signal.
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Poor Classroom
Classroom with a speech-to-noise ratio of 0 dB and a 1.5 second mid band reverberation time
Good Classroom
Classroom with a speech-to-noise ratio of 15 dB and a 0.5 second mid band reverberation time
These auralizations were created using a nearly anechoic children's audio book recording and HVAC noise measured in a classroom. Reverberation was added to the speech signal using the Full Reverb effect in Adobe Audition was added to the noise in Adobe Audition. The audiobook was recorded by Franny Joyce for the Project Gutenberg who owns the copyright for this work.
These animations, auralizations, and visualizations are © 2006 by Ralph T. Muehleisen and are licenced under a Creative Commons Attribution-NonCommercial 2.5 License.
HomeDiffractionWavesRoom ModesReverb TimeTransmissionNoiseClassroom Hearing Loss
Hearing Loss Auralization The following auralization was developed to show the effects of neurosensoral hearing loss on the intelligibility of female speech. Below are shown the typical hearing attenuation of someone with moderate and severe hearing loss along with photographs showing the cilia damage in the cochlea that could produce each condition
Hearing Loss
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None
Moderate
Attenuation Curve
Cochlea Photo
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Severe
These auralizations were created by applying frequency dependent attenuation to an anechoic recording of the female voice using Adobe Auditon. The attenuation curves for the three conditions were taken from a web page at the University of Wisconsin. These auralizations only show the effects of attenuation - they do not include any additional distortions that occur in addition to the attenuation with neuro-sensory hearing loss. As a result, these auralizations are only a very rough approximation to the sound perceptions of people who have hearing impairments.
The female voice in these auralizations comes from the Bang and Olufsen "Music for Archimedes" CD, © Bang and Olufsen and are used for educational purposes under Section 107 of the Copyright Act. As a result, this page has limited distribution and uncontrolled public access of those portions which include copyrighted content is not allowed.
These animations, auralizations, and visualizations are © 2006 by Ralph T. Muehleisen and are licenced under a Creative Commons Attribution-NonCommercial 2.5 License.
COMSOL Model Report
1. Table of Contents ● ● ● ● ● ● ● ● ● ●
Title - COMSOL Model Report Table of Contents Model Properties Constants Global Expressions Geometry Geom1 Solver Settings Postprocessing Variables
2. Model Properties Property
Value
Model name Author Company Department Reference URL Saved date
Nov 24, 2006 11:05:27 PM
Creation date
Nov 17, 2006 4:07:23 PM
COMSOL version
COMSOL 3.3.0.405
File name: D:\research\ASA Talks\f06\animations\visualizations\diffraction\barrier h=lambda.mph Application modes and modules used in this model: ●
Geom1 (2D) ❍ Pressure Acoustics (Acoustics Module)
3. Constants
Name
Expression
Value Description
f0
25
x0
2
y0
2
c0
200
rho0
1.21
p0
1
t0
1/f0
lambda0
c0/f0
h0
8
height of barrier
hol
h0/lambda0
ratio of height to lambda
frequency
speed of sound m/s
4. Global Expressions Name Expression
Description
gt
(t
