sdngnet.comsdngnet.com/Files/Lectures/FUTA-ARC-507/Assignments/2009... · Web vieware calculated from its component properties based on the standards NF EN 12354-1 and 2.Therefore,

EXAMPLES OF ACOUSTIC SOFTWARE

A WRITE UP

ON

EXAMPLES OF COMPUTER SOFTWARES FOR ACOUSTIC ANALYSIS.

BY

ADEKANYE PETER ADEBISIARC / 04 / 3164

COURSE.ARC 507

ENVIRONMENTAL CONTROL III.(ACOUSTICS AND NOISE CONTROL)

COURSE LECTURER.PROF. OLU OLA OGUNSOTE

SUBMITTED TO

THE DEPARTMENT OF ARCHITECTURE

SCHOOL OF ENVIRONMENTAL TECHNOLOGY

FEDERAL UNIVERSITY OF TECHNOLOGY, AKURE

IN PARTIAL FULLFILMENT OF THE REQUIREMENT FOR THE AWARD OF A BACHELOR OF TECHNOLOGY (B.TECH) IN ARCHITECTURE

MARCH 2009

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TABLE OF CONTENTS

1.0 INTRODUCTION

1.2 SOUND1.2.1 Sound Simulation

1.3 ACOUSTIC1.3.1 Acoustical Simulation

2.0 ACOUSTIC SOFTWARES2.1 ARCHITECTURE ACOUSTICS

2.1.1 EXAMPLES OF ARCHITECTURAL ACOUSTIC SOFTWARE

2.1.1.1 AAD Software2.1.1.2 REFLEX2.1.1.3 BEASY2.1.1.4 Hypersignal-Acoustic Software2.1.1.5 Acoubat Sound2.1.1.6 CARMEN®2.1.1.7 DAAD2.1.1.8 NEMPEE ACOUSTICS SOFTWARE

2.2 ENVIRONMENTAL ACOUSTIC2.2.1 EXAMPLES OF ENVIRONMENTAL ACOUSTIC

2.2.1.1 MICADO2.2.1.2 MITHRA®2.2.1.3 DSP

2.3 Underwater Acoustic Analysis System (UAAS)CONCLUSIONREFERENCE

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INTRODUCTION

The human kind has been interested in acoustics for long years.

Many mosques, churches, concert halls still stand as an evidence

of this great interest. For instance, the open-air theatre in ancient

Greek cities, such as Aspendos with its excellent acoustic,

similarly the Ephesus theatre still hosting for concerts and Hagia

Sofia in Istanbul can be shown as the best examples. Today the

architectural acoustic is considered as an interdisciplinary subject.

The demand for the use of computers in acoustic design has led

to the rapid growth of the increase of room acoustic software.

1.2 SOUND

The sound is defined as pressure variations perceptible by human

and it is relatively more difficult to measure than temperature or

pressure, because it occurs over a range of distinct frequencies.

Therefore it must be measured at each frequency. Although a

human ear can hear the sound between 20 Hz and 16.000 Hz,

acousticians mostly interest in sounds ranging from 44 to 11,300

Hz. In spite of this range, measuring sound is still not easy,

because measuring at each frequency results in 11.256 data

points per reading. In order to avoid deal with a huge number of 3


data the interval is divided into sub intervals called octave bands

and each octave band is limited by a lower frequency and an

upper frequency which is twice its lower frequency. Because of

this limitation, eight octave bands are obtained with center

frequencies of 63, 125, 250, 500, 1000, 2000, 4000 and 8000 Hz

and therefore, acoustic calculations are done for each of this

octave band.

1.2.1 Sound Simulation

Sound simulation is a broad topic that has been studied for

decades and lots of methods have been applied for simulation so

far. Mathematically the wave equations are used to describe the

sound propagation but they are not easily applied to computer

simulation of sound. Therefore there are mainly two approaches

which approximate the solution (Savioja, 1999).

• Wave-based methods

• Geometric methods

1.3 ACOUSTIC: this is the science of sound. It involves the

analysis of the properties of sound.

1.3.1 Acoustical Simulation: The studies on acoustical

simulation software have a rapid growth in last 20 years. The

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main purpose of acoustical simulation is to simulate the

propagation of the sound into computer in order to get an idea

about the room acoustic. The process of acoustical simulation

software has three main parts;

Source conception which deals with how the sound is emitted. Modeling method of room which is the most important part of the sound simulation software and is also important for the correct parameters. Modeling of receiver.

2.0 ACOUSTIC SOFTWARES

In order to solve acoustic challenges, reduce its adverse and

maximize its efficacy researchers have developed computer

softwares. These softwares have been developed according to the

nature of the acoustic environment, these include;

Architectural AcousticsEnvironmental Acoustics Underwater Acoustic Analysis System (UAAS)

2.1 Architecture Acoustics: these are acoustic softwares

designed basically for acoustic analysis of buildings. Some of

these softwares are developed for acoustic analysis during the

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design or after construction. The analysis done by these softwares

include;

Reverberation Auralization Room acoustic prediction

Sound insulation Anechoic signals Spectral

analysis etc.

2.1.1 Examples Of Architectural Acoustic Software: so as to

solve architectural acoustic challenges, varieties of softwares

have been developed, some of which include;

AAD NEMPEECATT Ramsete/ AuroraOdeon REFLEXBEASY DAADACOUBAT ® CARMEN®SLAB ICAREPARABOLE MEFISSTO CASC ATLAS 4AS 2.1.1.1 AAD Software (Architectural Acoustic Design) has been

designed for easy to use with using a ray-based method which is

ray tracing. This program is used for not only the rooms already

constructed, but may also be used for the rooms being built. AAD

application is developed using Microsoft Visual C++ with MFC for

Windows platform. It requires minimum, Intel Pentium based CPU

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with 64 Mb RAM and 16 MB VGA which supporting OpenGL (Enis

ÖZGÜR 2003).

Architectural Acoustic Software can be evaluated in two

categories.

3D room design and

Sound modeling.

3D Room Design

The sound source, receiver and the walls are designed by using the objects

created in AScene classes. The user gives the material properties while creating

the objects. Unlike the other programs, AAD enables the room to be

drawn with a 3D modeling tool because of its easy data input. In

AAD the number of shapes that is used for designing a room is

eight, i.e. dome, cube, cuboids, etc

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Figure 3 sound modeling

interface


Sound Modeling For modeling of the sound, the ray tracing method has been

chosen, which is the most commonly used. However, its long

computational time is a disadvantage.

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Fig. 1: 3D room design interface Fig. 2: Ashape modifier tool

Figure 3 REFLEX sound

absorb interface


2.1.1.2 REFLEX: this is a room acoustics software application developed in

1989 by MJM ACOUSTICAL CONSULTANTS INC with the help of the department of

architecture and mathematics of University of Montréal (MJM web 12:55am).

With REFLEX one can visualize the spatial distribution of the first reflexions on the

boundaries of a room, and reorient automatically surfaces to redirect sound

reflexions where they are required. This last feature allows the acoustical

designer to address the spatialization of a room, an aspect of room acoustics

which is often left aside because of the lack of proper tools to address it.

REFLEX is designed to be used with AUTOCAD: it is a powerful design tool which

actually allows the acoustical designer to modify the design of the room. Among

other things REFLEX allows to:

Identify areas where useful reflexions occur on a wall or ceiling surface;

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http://www.mjm.qc.ca/en/reflex/image2_p.html


Figure 4: REFLEX 3D sound modeling


Determine the surfaces likely to generate long delayed reflexions (echoes),

or sound focalization;

Locate and optimize the areas of a room where sound absorptive treatment

is required;

Orient acoustical reflectors to optimize the acoustic spatialization of a room

by redirecting first reflexions with the proper delay and angle of incidence

where they are most needed.

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2.1.1.3 BEASY: this enables offending noise sources to be

eliminated at the design stage by simulating the acoustic performance as part of

the design and analysis cycle (BEASY web 07:43pm). Beasy is used for

Environmental noise control, Architecture and Engineering Design. Beasy

software analysis is in two modes, they are;

1. Root Cause Analysis

Sensitivity analysis Panel contribution analysis

2. Diagnostic Analysis

BEASY Acoustic Design provides not only predictive tools for a wide range of

acoustic problems but also introduces powerful diagnostic technology to identify

the root cause of acoustic problems. Powerful panel contribution techniques can

identify the exact contribution of individual elements or structural panels to the

sound observed at a point. The sensitivity of the sound to the structure velocity

and surface condition (impedance) also provides key design information for the

designer.

Analysis Features

Comprehensive checking of data and of the required computer resources

ensures that no analysis runs are wasted

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http://www.beasy.com/


Local error guides to give clear indication of solution accuracy

Multi-frequency Analysis

Efficient and economical solution at as many user-specified “internal

points” as required

Step-by-step analysis option allows re-analysis to be carried out after minor

changes without recalculation of element matrices

Interfaces with finite element and experimental data

NASTRAN FEM interface General Interface for importing test-structural velocity data

Benefits

Simple and cost effective noise prediction

Noise control and reduction

Structural acoustic scattering and radiation

Vibro acoustics

Prediction of interior and exterior noise fields

Scattering of sound by obstacles

Prediction of acoustic efficiency

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2.1.1.4 Hypersignal-Acoustic Software

Hypersignal-Acoustic is a superset of Hypersignal-Macro software(signalogic web

09:08 pm). Below is a partial description of functions and display/instrument

options found only in Hypersignal-Acoustic software:

Equalization

Input for equalization processing in Hypersignal-Acoustic can come from either real-time Spectrum Analyzer analog input channels, or from waveform files. It can be used to equalize the original magnitude response; it can also be applied in real-time using the Real-Time Convolver™ software add-on.

1/N Octave Band Display Option in Spectrum Analyzer

The 1/N Octave Band display option allows log-magnitude traces (either real-time analog input or waveform file input) to be viewed in common acoustic/audio formats such as 1/3, 1/6, and 1/12 octave band.

MLS Stimulus & Response

The MLS (maximum length sequence) stimulus & response function in Hypersignal-Acoustic includes user inputs such as stimulus length, number of averages, output waveform filename, sampling frequency, channel list, and stimulus amplitude and offset.

Distortion Measurement

The distortion measurement function in Hypersignal-Acoustic uses the noise generator option in the Spectrum Analyzer to send a specified sine wave to the installed DSP/analog hardware D/A output while the analyzer is running.

Schroeder Integration

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The Schroeder integration function in Hypersignal-Acoustic uses a

difference equation to calculate ”reverse time integration" and save the

results to an output time domain waveform file.

2.1.1.5 Acoubat Sound: this is used to evaluate the acoustics insulation of

buildings. Within the framework of the French building code, Acoubat Sound allows

the evaluation of the impact of sound on buildings. Acoubat Sound makes it easy to

determine an optimal acoustic solution for multifamily apartments, offices,

classrooms, hospital rooms, etc. Once equipped with a sound card and a headphone

(or two loudspeakers), your PC will allow you to experience the noise in a given part

of the building, whatever its source, its nature and its level (32 predefined sources

of noises are available).

Acoubat is software that permits the calculation of sound and impact noise

insulation in buildings. In this software, the acoustic performances for the building

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Figure 5: Hypersignal-Acoustic output


are calculated from its component properties based on the standards NF EN 12354-

1 and 2.

Therefore, the user can directly appreciate the influence of the direct transmission

and of the various other different paths to modify its calculation and find a solution

that complies with regulation

Furthermore for an acoustician, the calculation detail is given up to the vibration

transmission index at the junction. This index, not included in the data base, is

calculated from the characteristics of the walls considered.

2.1.1.6 CARMEN® is an interactive system which allows a hall's acoustics to be

adapted to suit each type of presentation (plays, operas, concerts) by modifying the

period of reverberation for instance. Its principle involves the creation of active

virtual walls, composed of a range of cells combining a microphone and

loudspeaker, distributed throughout the hall and its ceiling.

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Figure 6: 3D model showing application of CARMEN cell


2.1.1.7 DAAD

DAAD which stands for Dokuz Eylul Architectural Acoustic Design software, deals

with the exact calculation of the impulse response, aims to design an amendable

acoustic simulation program by using basic modelling methods. It is used for

calculating acoustic parameters of large scale spaces like concert halls and

auditorium that are given by ISO as well as 3D modelling and visualization of the

building(Ozgura, Ozisb, Alpkocak 2004).

The software provides user friendly interfaces to design rooms in 3D environments

and to locate the receiver and the sound source at desired positions. It determines

the characteristics of the room by using ray tracing method. Finally, system allows

users to listen to the sound affected by room acoustics at receiver position. The

system was developed by using Microsoft Visual C++ 6.0, OpenGL 1.2, and Intel C+

+ Compiler under Windows NT platform.

ROOM MODELLING TOOL: The Room Modelling Tool (RMT) of DAAD provides the

complete solution for architectural acoustics design in order to help acousticians

modify the room object and its materials easily. It also provides interfaces to locate

all the objects (such as walls, surfaces etc.) and the absorption coefficients are

easily set.

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DAAD Room Modeling Tools


Figure 7:

SOURCE AND RECEIVER MODELING: The source and receiver modeling is an

important issue in room acoustic where improper receiver modeling eventually

leads to multiple detection, diminished detection or wrong detection. DAAD uses

point sources. DAAD uses the model presented by Xiangyang et.al [8] for receivers,

where the receiver volume is a function of the number of rays, the distance

between the source and the receiver and the volume of the room.

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RECEIVER

SOURCE


Figure 8: DAAD Source and receive location

DAAD is capable to calculate acoustical parameters given by ISO as well as 3D

modeling and visualization of the building.

2.1.1.8 NEMPEE ACOUSTICS SOFTWAREThis is a powerful Software tool for Acoustics Engineers & Architects. Based on

Mathematical calculations, it determines the acoustical parameters of a room, such

as the reverberation time. Measurement System can be in Meters or Feet. Nempee

acoustics software is used to obtain;

Detailed calculations of reverberation time over a wide spectrum of audio frequencies.Detailed study of modal & resonance frequencies.Choice of Acoustical material based on their performance across the whole spectrum.

The Technique To Follow

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Calculate the required quantity of absorption material with the help of NEMPE Acoustics Software.

The location of the absorbent material is to be worked out according to rules accepted by experience.

Reverberation measurements are taken after the room is completed &

modifications, if necessary, should be done to obtain the desired reverberation.

2.2 ENVIRONMENTAL ACOUSTIC: These are acoustic softwares basically for

outdoor space. Most often than not they are applied in the design of rail stations,

bus terminals, airports etc

2.2.1 Examples of Environmental Acoustic. They include;

MITHRA® MICADO

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Figure 9: NEEMPEE Acoustic Software interface


DSP etc.

2.2.1.1 MICADO: A French acronym for “Integral Method for the Acoustic

Calculation of Obstacle Diffraction”. The MICADO software package is a high-tech

tool developed by CSTB researchers, it is used during the design stage to optimise

the effectiveness of noise barriers of complex shape and materials. Its optimised

design makes it ideal for modelling complex situations, such as the repeated sound

reverberation between a train and a noise barrier.

The design code also takes into account the nature of the ground (grass, cultivated field,

bitumen, ballast, etc.) and complex sources of noise such as that produced by a train wheel

running along a track. The precision of both the geometric and acoustic representations

produces optimum effectiveness.

This software offers the possibility, when designing a noise barrier, of optimising shapes and

materials, and conciliating performance and appearance, in collaboration with the landscape

gardener and architect. To increase the effectiveness of noise barriers in protecting homes

without increasing their height, MICADO also dimensions diffractors at the top of noise barriers

(absorbent cylinders, absorbent tees, capping, etc.).

2.2.1.2 MITHRA® simulates the external sound environment of major projects,

industrial installations and major construction sites. It evaluates noise levels around

transport infrastructures (roads and railways), integrating the effects of different

types of soil, topography and weather on the propagation of noise over long

distances.

2.2.1.3 DSP: the DSP software is applied in a Train Station St. Gallen in

Switzerland. This is applied by adjusting the announcement sound level in real time

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Interface of the DSP software


by an ambient noise compensation algorithm (integrated in the DSP software, which

"listens" to the ambient sound by specially installed listening microphones). As soon

as the noise level drops to normal levels, the announcement is set back to regular

volume. A special timing option offers abation of the volume correction at night in

consideration of the quality of life of the local residents.

2.3 Underwater Acoustic Analysis System (UAAS): this is the German variant of the generic post analysis system (GSPAS) for the assessment and analysis of sonar signals received from submarines, curface ships, MPA, and other sources. It is specifically designed for Navy.

CONCLUSION:

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Today, the computer aided engineering has been developing day by day and the engineering problems are solved by computers in fast and robust. The testing of an engineering problem in real life costs too much money but to test it in virtual environment of the computers is very cheaper and faster.

REFERENCE

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1. Enis Ozgura, Feridun Ozisb, Adil Alpkocak (2004), DAAD: A New Software for Architectural Acoustic Design, The 33rd International Congress and Exposition on Noise Control Engineering.

2. Lauri Savioja (1999), Modeling Techniques for Virtual Acoustics, PhD dissertation, Helsinki University of Technology, Department of Computer Science and Engineering.

3. Özgür Enis, “Design and Development of an Architectural Acoustic

Design Software”, MSc thesis, Dokuz Eylül University, Department of

Computer Science and Engineering

WEB1, (2009), Nempee Audio’s web site, www.nempee.com/ ,

17/03/2009.

WEB2, (2009), CATT’s web site, www.catt.se/ , 17/03/2009.

WEB3, (2009), Ramset/Aurora’s web site, www.ramsete.com/

17/03/2009.

WEB4, (2009), Beasy web site http://www.beasy.com/ 15/03/2009

WEB5, (2009), http://hsi.arc.nasa.gov/publications/ 17/03/2009.

WEB6, (2009), Signalogic web site http://www.signalogic.com/ 15/03/2009

WEB7, (2009),CSTB web site http://sotware .cstb.fr/ 17/03/2009

WEB8, (2009), RELEX web site http://www.mjm.qc.ca/ 15/03/09

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http://www.mjm.qc.ca/

http://www.signalogic.com/

http://hsi.arc.nasa.gov/publications/

http://www.beasy.com/

http://www.ramsete.com/

http://www.nempee.com/


CATT-Acoustic

To use CATT-Acoustic, detailed information on room geometry and wall materials is required and the frequency range is often limited to the octave-bands 125 Hz to 4 (or 8) kHz, simply because of lack of available material data for the higher octaves. CATT-Acoustic extrapolates the higher octaves for auralization. This approach is based on prediction since it analyzes a room and the resulting response will sound according to the design of the room.A demo version of the software is downloaded

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Documents

sdngnet.comsdngnet.com/Files/Lectures/FUTA-ARC-507/Assignments/2009... · Web vieware calculated from its component properties based on the standards NF EN 12354-1 and 2.Therefore,