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Applied Acoustics course (6 CFU)

in academic year 2012/2013 this course is taught in English
Click Here for accessing the previous-year page (in Italian)

Post-Graduate (advanced) degrees: Telecommunication Engineering, Electronics Engineering, Computer Engineering and Mechanical Engineering

Under-Graduate degree: Civil and Environmental Engineering and Management Engineering

Under-Graduate degree: Techniques of Prevention in the Environment and at the Workplace


Teaching Hours:   Friday 14.30-18.30 (classroom 7, Engineering Faculty, University Campus)

Beginning of the course: Friday 05/10/2012

Lecturer: prof. Angelo Farina

E-MAIL: farina@unipr.it

Website: http://pcfarina.eng.unipr.it/ or http://www.angelofarina.it/

Receiving hours: Monday, 10:30 to 12:30 - building 7 (not recommended - better to use email).

WARNING! during lesson period (from 04/02/2013 to 31/05/2013), the receiving will occur on Friday, 8.30 to 10.30.

Phone Number: 0521-905854 (not recommended)

Contents

 

Introduction

The course of Applied Acoustics is an introductory course to a scientific and technological field undergoing a very rapid development, which offers great employment opportunities, and which involves disciplines apparently very different: architecture, structural engineering, physiology, psychology, statistics, physics, electronics, vibration mechanics, fluid dynamics, digital signal processing, telecommunications, measurements, hygiene of the workplace, music, musicology, virtual reality.

Obviously in a course of 6 CFUs we can only provide the methodological basis of the topic, which must then be furthered in more in-depth courses, such as courses for Competent Technicians in Environmental Acoustics or Master Courses available at some Italian or foreign universities (for example Perugia , Naples , Florence , Rome), or even dedicated post-graduate degrees (these are usually abroad, but in Italy it must be evidenced the post-graduate (advanced) degree in Sound and Music Engineering of Politecnico di Milano, taught entirely in English, delivered at the Como Campus).

Because of its multidisciplinary and transversal nature, the Course of Applied Acoustics is attended by students from various degree programs (almost all branches of Engineering, but also some Architecture students, and even the students of the course in Techniques of Prevention in the Environment and at the Workplace of the Faculty of Medicine, for which attendance is compulsory only to the first part of the course, with the exclusion of the final part dedicated to electroacoustic and musical applications).

For students of all branches of engineering this is a key course, it is practically the only opportunity to see (or, rather, hear) the techniques learned in previous courses, in which the purely theoretical foundations of modern advanced mathematical methods are taught. When the "numbers" are transformed into sound, abstruse and difficult mathematical procedures quickly become very clear and immediate, and the possibilities offered by sound editing systems on the PC, used extensively both during lectures and during laboratory exercises, make it possible to listen immediately (usually in real time) to the "effects" of filters or other devices (compressors, gates, convolvers, denoising, etc.).

EXAMPLE:

Many students do not understand the physical meaning of "differentiation" and "integration" operators applied to a function. Math teachers tend to give "graphical" explanations , such as "the derivative is the slope of a curve" or "the integral is the area under a curve." These explanations are useless for those who are devoid of the capacity of visualisation needed to transform these concepts into images, and / or these images in understanding what happens to the function that is differentiated or integrated.

In acoustics, the operations of differentiation or integration modify the spectrum of a sound. In particular, differentiation boosts high frequencies (increases the sound level of 6dB/octave). On the contrary, integration boosts low frequencies. Here's an example, which allows to "listen" to differentiation and integration applied to a recording of the human voice:

Original.mp3

Differentiated.mp3

Integrated.mp3

A more extended presentation of this topic is developed in this web page

Given the scientific interests of the teacher, the course covers both the noise-related topics common to all branches of engineering and hygienistics (also as a consequence of the extensive legislative framework on buildings, environment and workplace), and the more specific themes relative to the acoustics of theatres and cinemas, audio production in music and television / film, musical instruments, high fidelity recording and Stereo (1D), Surround (2D) and three-dimensional (3D) playback systems. Obviously, this second part of the course is not pertinent to students of the degree in Techniques of Prevention, who have a program limited to the first 3 CFUs of the course.


Program of the Applied Acoustics course  

  • Physical Acoustics: definition of quantities, propagation of mechanical disturbances in an elastic medium, sound pressure, particle velocity, speed of the sound wave. Equation of the acoustic waves.
  • Energetical Acoustics: sound propagation seen as energy transport. Definition of Sound Intensity and Sound Energy Density. Active and Reactive energy, propagating and stationary sound fields. The Reactivity Ratio (or index).
  • Psychoacoustics: physiological and psychological mechanisms of sound perception by humans. The logarithmic scale of decibels (dB), elementary operations on quantities expressed in dB. Frequency weighting curves, methods of Loudness assessment, frequency analysis with constant bandwidth, with constant percentage bandwidth (octaves, etc.), with critical bands (Bark). Masking phenomena in time and in frequency. Use of psychoacoustics for encoding "lossy" and "lossless" audio signals with large reduction of the "bitrate" required (MP3, WMA, AAC, FLAC, OGG, etc.).
  • Sound Propagation: plane waves, spherical waves, standing waves. Reflection and absorption. Specular and diffuse reflection . Definition of sound absorption coeff. and scattering coeff. . Measurement techniques of the absorption coeff. and of the scattering coeff. .
  • Propagation outdoors: ground absorption, effect of temperature and wind gradients, of air absorption, of shielding or obstacles. The Maekawa and Kurze-Anderson formulas for the estimation of shielding attenuation.
  • Propagation indoors: the phenomenon of multiple reflections, stationary reverberant field. Formulas of the reverberant field and of the semi-reverberant field. Transients when a sound source is switched on and off: sound tail, impulse response of a room, Schroeder backward integration. Definition of Reverberation Time T60 and other quantities related to the acoustic transients. Sabine formula for the estimation of the reverberation time. The apparent sound absorption coefficient, and its measurement by tests in reverberation room.
  • Propagation through building structures: insulation of partitions, windows, tapping noise. Measurement techniques and Italian law.
  • Digital Signal Processing applied to audio and acoustics. Sampling sound, artefacts due to limited amplitude resolution and temporal discretization. Basic algorithms for digital filtering (FIR, IIR): a complex theory made easy. The FFT algorithm, fast convolution, partitioned convolution. Effects of nonlinearities and of time variance.
  • Advanced method for impulse response measurement (MLS, ESS, etc.). Sound quality in concert halls and opera houses. ISO3382 acoustical parameters. Temporal and spatial parameters. Use of directive microphones for assessing the spatial properties of the sound field inside a room.
  • Speech intelligibility in classrooms, auditoria and over telecommunication systems. The signal-to-noise ratio, effect of reflections and reverb. The Speech Transmission Index (STI) and its measurement.
  • Electroacoustics: transducers (microphones, loudspeakers). Devices for processing analog and digital acoustic signal: amplifiers, equalizers, reverbs, compressors, etc... Applications in the audio/electronics industry, in the field of telecommunications and broadcasting, in the recording industry and in entertainment industry automotive, in aviation and marine sectors.
  • Techniques for numerical simulation of sound propagation: finite element models, boundary elements, ray tracing, beam tracing. Using simulation programs, with hands-on practice in the laboratory. 
  • Instrumentation and equipment for acoustical measurements: sound level meter, spectrum analyzer, impulse response measurement system. Virtual Instrumentation on PC, software for acoustical measurements, with practical exercises in the laboratory.
  • Numerical processing of the acoustic signal: from general theory to practical applications on PCs. Auralization, virtual acoustics reality. Outline of modern applications in the entertainment industry, and future uses for "live" real time applications. "Plugins" for digital processing of acoustic effects; FIR and IIR filters, fast convolution, calculation of Inverse numerical filters, active cancellation of sound.
  • The 4 modern methods for measuring absorption coefficients: ISO 354 (reverberation room), ISO 10534 (standing wave tube), the Intensimetric Method (Farina/Torelli), the Impulsive Method (EN 1793/5).
  • lab sessions : measurement of impulse response and other major acoustic parameters employing Aurora, numerical simulation of the sound field inside a room by making use of two calculation programs (Ramsete, Comsol).

The first 7 topics (evidenced in blue) are common also to students of the degree in Techniques of Prevention (3 CFUs), while the remaining topics (in black) apply only to students of the Faculty of Engineering (6 CFUs).

Back to Top

For the "official" program and other information about the exam, please refer to the official websites:
- Official Page of the Mechanical Engineering degree
- Official Page of the Management Engineering degree
- Official Page of the Degree in Techniques of Prevention in the Environment and at the workplace .


Method of Examination

The examination is formally oral, but it is usually required to first carry out some written exercises in numerical form (so the student is required to carry pen, paper, a calculator, as well as charts, tables, handouts, etc..).

During the written exercises it is possible to employ all of the above material, including a computer, handouts and/or textbooks; instead, during the final oral "theoretical" question, the student is not allowed to consult his handouts or books, but he can still employ charts and tables - so it is advisable to keep them separate from the handouts.

The written exercises typically provide a a score up to 25-30 points. At least 15 points are required for passing the written exercises and being admitted to the subsequent oral question, which is mandatory, and provides +/-10 points. At least one written exercise is always mandatory, even for students who take the examination during receiving hours (see later).

Students of the Engineering courses are requested to use English both for the written and oral parts of the examination, even if they followed the course in previous years, when it was named "Acustica Applicata" and taught in Italian.

Students of the degree in Techniques of Prevention, instead, are allowed to take the examination in Italian, if preferred, although of course they are also allowed to take it in English, at their choice.

The oral examination is MANDATORY, even for students who passed the written exercise with maximum score. The evaluation of the oral examination, which usually is positive, in some cases can provide a NEGATIVE score, reducing the score obtained in the written part. And, independently from the sum of the scores, if the oral examination is judged unsatisfactory, the student can always be rejected.

So the students must be trained to sustain a formal oral examination, and are discouraged to only train on exercises.

For optimal training to the oral examinations, the students are encouraged to assist to the previous session of exams.

For optimal training to the exercises, it is strongly discouraged to "study" the solution of already-solved problems. The only way to be trained correctly is by attempting to solve problems without any preliminary knowledge of the correct solution. For this, it can be useful to download the text of the problems which were employed in past years, during the written exam of Technical Physics, which can be downloaded here:

T E S T I _ E S A M E


Dates of exams

Date

Day

Hour

Place

07/09/2012

Friday

9.00

didactics site

28/09/2012

Friday

9.00

didactics site

11/02/2013

Monday

9.00

Aula B

01/03/2013

Friday

9.00

Aula B

08/04/2013

Monday

9.00

Aula 3

01/07/2013

Monday

9.00

Aula 8

12/07/2013

Friday

9.00

Aula 8

26/07/2013

Friday

9.00

Aula 8

13/09/2013

Friday

9.00

Aula A

24/09/2013

Tuesday

9.00

Aula B1

Currently, the Easytest software does not allow to plan the exam dates with large advance, so the students are kindly requested to be patient, and do not stress the teacher asking to fix the exam dates. This is currently outside the control of the teacher, and such requests are absolutely not useful. The students are simply recommended to check this web page often, when the dates are fixed they will be posted immediately here. In any case, the teacher will not answer to requests of fixing additional exams, as it is possible to make exams every week, during the receiving hours, as explained below.


Examinations in receiving hours

Students may ask the teacher to take the exam in dates different from the "official" ones shown above, by sending an E-mail for according about date and site for the exam. In particular, the general rule is to perform these exams during receiving hours, even if it is always required to get a preliminary agreement by E-mail.

Every student is required to check with the Secretary that he is allowed to take the exam on the chosen date - if he is not allowed, the Secretary cancels the exam's recording, and it must be repeated ....

For clarity: who does the exam in receiving hours gets immediate verbalization of the examination carried out. Therefore it needs to be ensured that the student is allowed to take the exam on the date on which it actually takes place. Under no circumstances the examinator will leave a "suspended verbalization" until the next exam session. Who is not allowed to take the exam on a certain date, of course cannot do it at that time. These rules were made for presumably good reasons, so they should not be circumvented. If they are deemed inappropriate, students should ask the Faculty to change them, rather than bombard the lecturer with requests of improper circumvention of the rule...

On the other hand, these rules are complex, and the position of each student is, in general, different from that of another. I do not have the knowledge and the tools to determining who is entitled to make an examination on a certain date and who is not. It is useless to ask me, for me everyone can do the exam at any time... Every student must check with the Secretary, to avoid that the examination is cancelled, after being done in a "not allowed" date.


Laboratory sessions

Three lab sessions of 4 h each will be held at the CEDI (Didactical Engineering Center, building B, CAD-CAM lab), in the month of January, 2013. The dates are as follows:

Date

Time

Place

15/01/2013

14:30 to 18:30

CAD-CAM Lab (Pal.B, scientific engineering buildings, 1st floor)

20/01/2013

09:00 to 13:00

CAD-CAM Lab (Pal.B, scientific engineering buildings, 1st floor)

22/01/2013

09:00 to 13:00

CAD-CAM Lab (Pal.B, scientific engineering buildings, 1st floor)

During the first lab session acoustical tests are performed employing a powerful dodechaedron loudspeaker: of consequence, students are encouraged to carry proper personal protective equipment. We recommend "disposable" earplugs (Ear, Bilsom, etc..).

Students in possession of a laptop are invited to bring it in the classroom, but only if it features:

  1. External microphone (wired), preferably of cylindrical shape (so that it can be inserted in the calibrator). Also headphones equipped with microphone are suitable (at a lesser extent). In laboratory a number microphones is provided, but their use is primarily for computers installed in the classroom.
  2. Headphones (to listen to the auralization results without disturbing colleagues).
  3. Software Adobe Audition with Aurora plugins, or Audacity with Aurora-for-Audacity plugins (1st session)
  4. Software Ramsete (2nd session)
  5. Software DISIA (3rd session)


Recommended textbooks

The official textbook for the Applied Acoustics course is:

The books RECOMMENDED (not required) for thorough preparation of the exam are:

The support material for the course (Powerpoint presentations, Excel spreadsheets, WAV files, etc..) used during the lessons is available in the "Public" section of this website:
http://pcfarina.eng.unipr.it/Public/Acoustics-Course/- It is recommended to download especially Powerpoint slides and Excel spreadsheets containing the exercises done in the classroom.


Old "on line" handouts (in Italian)

It can be useful to download the material prepared some years ago for the Advanced Training Course for Competent Technicians in Environmental Acoustics , organized by the University of Parma in 2005 and 2006. It consists of 11 handouts covering the first part of the program (the one which covers the topics common also to the students of the Degree in Techniques of Prevention).

N (%)

Topics:

1

01 Misura Grandezze Fisiche.doc

2

02 Il suono - natura e grandezze caratteristiche.doc

3

03 Sistema uditivo - decibel - somma di livelli.doc

4

04 Fonometria.doc

5

05 Analisi Spettrale.doc

6

06 Tecniche digitali di misurazione acustica.doc

7

07 Propagazione in Campo Libero.doc

8

08 Barriere antirumore.doc

9

09 Acustica Ambienti Chiusi.doc

10

10 Assorbimento - Isolamento.doc

11

11 Misura Assorbimento Acustico.doc

Furthermore, the "on line" handouts of the old course of Technical Physics are available, which had been prepared by the students of the time. This course contained a part of about 30 hours of Acoustics, with e program covering, at least partially, the program of the current Applied Acoustics course. In reality they covered it almost completely: in fact, they even did a couple of things that are not done anymore, because the average level of the students of the old, five-years degree, was vastly superior to the average level of current students, and you could go away very fast on a wide range of subjects, instead now everything must be explained starting from the grassroots level ...

The web pages from which you can download these handouts are:

Academic Year

Degree

List of Handouts

Format

1998/1999

Electronic Engineering

Handouts 98/99

DOC and HTML

1999/2000

Electronic Engineering

Handouts 99/00

DOC and HTML

2000/2001

Electronic Engineering

Handouts 00/01

DOC and HTML

2001/2002

Electronic Engineering

Handouts 01/02

DOC and HTML

2002/2003

Mechanical Engineering

Handouts 02/03

PDF


And finally
it is possible to find on the Internet a number of useful handouts on some of the course topics:
 
 

New "on line" handouts (in English)

During the current academic year, a new collection of handouts is organized. At the beginning of each lesson, a couple of students should offer themself to write the handout of the lesson. This has to be sent to the lecturer maximum two weeks after the lesson, as a properly-formatted Word document: it will be made available on the following web page, together with the Powerpoint files and the audio-video recordings:

Handouts of the Applied Acoustics course - ac.year 2012/2013

The students who contribute to the collection will be rewarded with up to 5 additional points at the exam score (depending on the quality of the handout produced), which will be added to the score obtained with the written exercise and with the oral examination (which is always MANDATORY for everyone, even if he has got maximum score in both the written excercise and due to the handout).

Instructions (in Italian) are available for guiding the students in writing these handouts. A DOT file (DOcument Template) to be used for creating properly-formatted handouts in Microsoft Word can be downloaded here.


A good set of handouts written in American English, covering the first half of the course (Noise Control) are available from the site of prof. J. S. Lamancusa at Penn State University: http://www.me.psu.edu/lamancusa/me458/ Please, have a look at the animations on that page!

In particular, the first 10 handouts, albeit not in the same order, cover perfectly the first part of this Applied Acoustics course, the one common also to the students of the Degree in Techniques of Prevention:

N.
Topic
1
Introduction to Noise Control
2
Fundamentals of Hearing
3
Human Response to Sound
4 Noise Metrics and Regulations
5
The Physics of Sound
6
Units and Levels
7
Instrumentation for Noise Measurements
8
Room Acoustics
9
Transmission Through Structures
10
Outdoor Sound Propagation

Additional support material for the course (Powerpoint presentations, Excel spreadsheets, WAV files, etc..) used during the lessons is available in the "Public" section of this website:
http://pcfarina.eng.unipr.it/Public/Acoustics-Course/ - It is recommended to download especially the Excel spreadsheets containing the exercises done in the classroom.


Audio / Video recording of the lessons

Starting from academic year 2010/2011, we are performing the audio / video recording of the lessons, in AVI format, thanks to the Open Source program CamStudio .

The following links point to the list of these recordings for the A.Y. 2010/2011, 2011/2012 and 2012/2013 (the latter will be updated as the lessons are made)

We recommend to use the Open Source program VLC Mediaplayer for viewing and listening to these AVI files on any platform (Win/Mac/Linux). We also recommend to first download the AVI files to a local directory, and then to open the files form the local HD employing VLC mediaplayer. Playing back directly in the browser, from the course web site, is NOT recommended...

These audio / video recordings are made available primarily to facilitate learning for students with disabilities, but all students can view them comfortably, providing an opportunity to recover, at least partially, the lack of presence in the classroom during the lesson.

It must be remembered, however, that attending the lessons in person is always the best way to assimilate the material. The various experiments in telematic didactics have shown, unfortunately, that the students get a level of preparation significantly lower than that obtainable with a good traditional "face to face" didactics.

This occurs due to the "intelligibility barrier" caused by the recording/playback "filter". This effect on the intelligibility of speech will be explained during the course...


On Line scientific papers

The course contains advanced research topics, which are not described in standard textbooks about Applied Acoustics. In particular, updated information is required regarding measurement techniques, methods of computer simulation, and modern technologies for recording and playback of three-dimensional sound.

Students who wish to explore these topics can download the scientific papers of the lecturer in PDF format from this Chronological List . Most of them are in English.

The papers recommended to read for the exam are the following:

N.

Author(s)

Title

Publisher

24

A. Farina

Nuove tendenze nell' acquisizione dei dati acustici: strumentazione, software, normativa

Atti del Convegno Nazionale RUMORE e VIBRAZIONI, Bologna e Modena, 20-24 Novembre 1990

26

A. Farina

Modelli matematici per la previsione della diffusione del suono

Acqua Aria, n. 3, pagg. 257-268, Marzo 1991

32

A. Farina , G. Raffellini

Potere fonoisolante di murature in laterizio: verifiche sperimentali di laboratorio e considerazioni applicative

Costruire In Laterizio, N. 23 pagg. 378-385 (Settembre-Ottobre 1991)

48

A. Farina , P. Galaverna, G. Truffelli

"RAMSETE" - un nuovo software per la previsione del campo sonoro in teatri, ambienti industriali ed ambiente esterno

Atti del XXII Congresso Nazionale AIA, Lecce, 13-15 aprile 1994

49

A. Farina

Tecniche di convoluzione applicate al trattamento di segnali sonori per prove di ascolto

Atti del XXII Congresso Nazionale AIA, Lecce, 13-15 aprile 1994

50

A. Cocchi - A. Farina - P. Fausti - R. Pompoli - G. Semprini

Prestazioni acustiche dei solai in laterizio

COSTRUIRE IN LATERIZIO n┬░ 38, MAR-APR 1994, p.156-163

87

Farina A., Brero G., Pollone G.

Computer code based on experimental results for acoustical mapping of urban areas

Proc. of NOISE & PLANNING 96, Pisa (28-31 May 1996)

88

Farina A., Brero G.

Computer code based on experimental results for designing sound reduction devices

Proc. of NOISE & PLANNING 96, Pisa (28-31 May 1996)

94

A. Farina, A. Torelli

Measurement of the sound absorption coefficient of materials with a new sound intensity technique

Pre-prints of the 102nd AES Conference, Berlin, 23-26 March 1997

97

A. Farina, F. Righini

Software implementation of an MLS analyzer, with tools for convolution, auralization and inverse filtering

Pre-prints of the 103rd AES Convention, New York, 26-29 September 1997

106

A. Farina, P. Fausti

Misure di isolamento, del rumore di calpestio e del tempo di riverberazione

atti del convegno Edilizia e Ambiente, Trento, 18-20 febbraio 1998

107

A. Farina

Valutazione di impatto acustico previsionale relativamente alle sorgenti pi¨ diffuse

Atti del Seminario sul tema "Acustica Ambientale - effetti sull'uomo e pianificazione del territorio" - Repubblica di S.Marino, 9 maggio 1998

119

A. Farina, P. Galaverna, M. Giabbani

Il processo di auralizzazione: metodologia ed esemplificazione

Atti del Convegno "L'acustica dei teatri storici: un bene culturale" - Ferrara, 4 novembre 1998

122

G. Fornari, A. Farina

Studio della propagazione del rumore in ambienti industriali bassi e vasti

Industria delle Bevande (ISSN 0390-0541), anno 27, n. 158, Dicembre 1998, pp. 585-596

125

A. Farina

Misurazioni e rilievi fonometrici

Atti del Seminario "L'acustica negli edifici e nelle cittÓ "- Firenze, 26 marzo 1999 

131

A. Farina

Propagazione sonora e previsione del rumore negli ambienti di lavoro

atti del seminario "rumore e vibrazioni negli ambienti di lavoro: dalla valutazione alla bonifica" - Modena, 23 settembre 1999

134

A. Farina

Simultaneous measurement of impulse response and distortion with a swept-sine technique

108th AES Convention, Paris 18-22 February 2000

164

A. Torger, A. Farina

Real-time partitioned convolution for Ambiophonics surround sound

2001 IEEE Workshop on Applications of Signal Processing to Audio and Acoustics - Mohonk Mountain House New Paltz, New York October 21-24, 2001.

179

A. Farina, A. Avanzini

Registrazione della risposta acustica delle sale da concerto per i posteri

Seminario AES-Italia "Workshop sulle tecniche di ripresa stereofoniche multicanale per le orchestre sinfoniche" - Adria, 16 maggio 2003

188

E. Armelloni, C. Giottoli, A. Farina

Implementation of Real-Time Partitioned Convolution on a DSP Board

2003 IEEE Workshop on Applications of Signal Processing to Audio and Acoustics - October 19-22, 2003, New Paltz, NY

200

A. Farina, L.Tronchin

Cap. 19 - Misure acustiche nei teatri e nelle sale

nel volume "Acustica Musicale ed Architettonica", UTET Libreria, Torino 2004, ISBN 88-7750 -941-4

226

A. Farina

Advancements in impulse response measurements by sine sweeps

122th AES Convention, Vienna, Austria, 5-8 May 2007

238

A. Farina

Impulse Response Measurements

23rd Nordic Sound Symposium, Bolkesj├Ş (Norway) 27 - 30 September 2007

244

Angelo Farina, Andrea Capra, Simone Campanini

La misura della risposta all'impulso per la caratterizzazione di sistemi acustici e vibrazionali

"Strumenti e metodi di misura per l'acustica e le vibrazioni" - Seminario in ricordo di Eugenio Mattei - Ancona, 21 settembre 2008

252

Angelo Farina, Andrea Capra, Lorenzo Chiesi, Leonardo Scopece

A Spherical Microphone Array For Synthesizing Virtual Directive Microphones In Live Broadcasting And In Post Production

40th AES Conference "Spatial Audio - Sense the Sound of Space", Tokyo, Japan, 8-10 October 2010

253 Leonardo Scopece, Angelo Farina, Andrea Capra 3D Virtual Microphone System - Sonda Microfonica ad Elevata Direttivita' Elettronica e Telecomunicazioni, n.1, Aprile 2011, pagg. 14-26 - ISSN: 0013-6123
254 Marco Binelli, Andrea Venturi, Alberto Amendola, Angelo Farina Experimental analysis of spatial properties of the sound field inside a car employing a spherical microphone array 130th AES Conference, London, 13-16 May 2011
255 Angelo Farina, Alberto Amendola, Andrea Capra, Christian Varani Spatial analysis of room impulse responses captured with a 32-capsules microphone array 130th AES Conference, London, 13-16 May 2011
256 Angelo Farina, Enrico Armelloni, Lorenzo Chiesi

Experimental Evaluation Of The Performances Of A New Pressure-Velocity 3D Probe Based On The Ambisonics Theory

4th international conference and exhibition on Underwater Acoustic Measurements: Technologies and Results - Kos (Greece), 20-24 June 2011
257 Leonardo Scopece, Angelo Farina, Andrea Capra

360 Degrees Video And Audio Recording And Broadcasting Employing A Parabolic Mirror Camera And A Spherical 32-Capsules Microphone Array

IBC 2011, Amsterdam, 8-11 September 2011
258 Angelo Farina, Lamberto Tronchin

New Measurement Technique For 3d Sound Characterization In Theatres

The Acoustics of Ancient Theatres Conference Patras, Greece, September 18-21, 2011
264 A. Farina, M. Binelli, A. Capra, E. Armelloni, S. Campanini, A. Amendola

Recording, Simulation and Reproduction of Spatial Soundfields by Spatial PCM Sampling (SPS)

International Seminar on Virtual Acoustics, Valencia (Spain), 24-25 November 2011
267 Angelo Farina, Lamberto Tronchin 3D Sound Characterisation in Theatres Employing Microphone Arrays
Acta Acustica united with Acustica, vol. 99, n.1, pp. 118-125, ISSN 1610-1928, January/February 2013

Software

This is the list of software used during the lessons and lab sessions, with links to download them.

Name

Description

Link

 Adobe Audition

Program for sound recording and playback, waveform editor, simple FFT analysis, sonogram, multitrack recorder, and it can act as a "host" program for plugins in three different formats (VST, Direct-X, XFM).

The recommended versions are 1.5 (the best one) and 3.0.

Please DO NOT USE version 2.0 or version CS 5.5 and following, as these are NOT compatible with Aurora plugins. And please, install the English version of Audition (and of any other program offering a multi-language interface!).

Furthermore, it is always mandatory to set the Regional Settings of your operating system (in Control Panel) to English-UK or similar, NEVER in Italian! This affects decimal separator, date, time and number formats... If this setting is incorrect, operations such as Copy and Paste to another program (i.e., Excel) are going to fail....

http://www.adobe.com/it/products/audition/

 Aurora

Suite of XFM plugins for Adobe Audition: generation of test signals (MLS, sweep) computation of the impulse response, acoustic parameters according to ISO 3382, calculation of inverse filters. Includes a fast convolution module, which is employed for performing auralization. 

See the warnings above for Audition regarding program version and regional settings

http://www.aurora-plugins.com

 AudioMulch

VST-Host general purpose program, programmable through the construction of block diagrams, coming with a wide range of effects. Shareware, easy to use. Versions for Windows and Mac

http://www.audiomulch.com

 Plogue Bidule

VST-Host general purpose program, programmable through the construction of block diagrams, coming with a wide range of effects. It is possible to create new effects. Shareware. Windows and Mac versions. It can also be used as a VST plugin inside another VST Host program.

http://www.plogue.com/

 SynthEdit

VST-Host program and compiler of VST plugins, programmable through the construction of block diagrams. Customizable interface with editable "skins". Contains an extensive library of graphical objects and of processing functions. Shareware. Better than Labview ....

http://www.synthedit.com/

 SpectraRTA

Spectral analysis in octaves, third octaves, and FFT, signal generator for acoustic testing, measurement of the reverberation time. Works with one or two channels, can be used to record and analyze WAV files.

http://www.soundtechnology.com/

 SpectraPLUS

FFT and fractional-octave frequency analysis, cross-spectrum, sonogram, waterfall, signal generator for acoustic testing, measurement of reverberation times. Works with one or two channels, can be used to record and analyze WAV files.

http://www.telebyte.com/pioneer/index.html

 Ramsete

Simulation of sound propagation in enclosed spaces and outdoors. Calculates the impulse response, and from it derives all the acoustical parameters. Includes a 3D CAD design module and a module for mapping results in colour or by isolevel curves. It also allows for the export of impulse responses in WAV format, for performing auralization.

http://www.ramsete.com

 Comsol

"Multiphysics" FEM simulator, which includes modules for Acoustics and Vibration. It allows for the study of wave type phenomena (resonance, interference, diffraction, etc..) at low and medium frequencies, using the Finite Elements method. Free trial license available for students.

http://www.comsol.com

 DISIA

The package includes Citymap and Disiapyr. These are programs for simulation of noise from road and rail traffic, which can operate both on a large scale (Citymap), and for detailed simulations (Disiapyr). They were developed as part of a DISIA project, funded by the Ministry of Environment, and are the reference computational models for the Italian fleet of vehicles.

http://pcfarina.eng.unipr.it/Public/DISIA

Note: the above software is commercial software or shareware (excluding the last one, which is free, but the use is restricted to institutional goals of public administrations, and protected by password), although most of them provide a free running mode for a limited period of time, or indefinitely but with reduced functionality. Users who do not like this approach, can use the following open-source software:

  Audacity

Simple "open source" program for sound recording / playback, with many editing effects; it also operates in multitrack. Supports all platforms (Windows, Mac, Linux). A port of Aurora plugins for Audacity is under development (thesis available).

The special version of Audacity containing some of the Aurora plugins so far developed can be downloaded HERE.

http://audacity.sourceforge.net/

 

http://pcfarina.eng.unipr.it/Public/Aurora-for-Audacity/

  Sonicbirth

Compiler for VST and AudioUnit plugis for Mac platform, with graphical interface of "block diagram" type. Interface customizable using editable "skins". It contains a wide library of graphic objects and processing functions. Similar to Synthedit, but less powerful and versatile.

http://sonicbirth.sourceforge.net/

 RoomEQ

JAVA application for the measurement of the impulse response of a room with Exponential Sine Sweep and calculation of equalization filters for sound systems. It includes a realtime spectrum analyzer, a realtime Sound Level Meter, and a reverberation time measurement module.

http://www.hometheatershack.com/roomeq/

 Psysound

Matlab suite of modules, with user interface developed for processing of audio signals and acoustic analysis of all kinds

http://psysound.wikidot.com/


Thesis Topics

A variety of thesis topics is available, for all the branches of Engineering. Some are listed below, but others are available, so it is recommended to contact the teacher for more information.

Attention: an Applied Acoustics thesis can only be experimental, and thus requires hard work: so, if you are looking for a "light and fast" thesis, you're in the wrong place ...
 

Title

Description

Suggested degree

Digital Audio Amplifier  

Research carried out in collaboration with ASK Industries, Reggio Emilia, looking for a student who is willing to learn programming DSP devices "embedded" in automotive audio amplifiers. The DSP built into the device could be used for active noise cancellation, for dynamically changing the equalization curve and the gain as a function of the background noise, and for the correction of non-linear response of loudspeakers. The student will work as an intern at the ASK Montecavolo (RE), actively participating in the trial, and gaining professional experience in the field, which is extremely useful for subsequent job search.

Electronics, Telecommunications, Computer Science

Vehicle sound system measurement

Research carried out in collaboration with ASK Industries, Reggio Emilia. The purpose is to evaluate the perceived acoustical quality of a "automotive" sound system, based on innovative measurement techniques (STI, AQT, PEAQ) and on listening tests performed within the vehicle or in a special playback room. It employs mono recording techniques, binaural, or array of microphones. Depending on the capacity of the student, he will have to develop "ad hoc" software for measurement or analysis (in Matlab or Visual C), to define new metrics, to analyze statistically the results of subjective tests, and to design new strategies for temporal, spectral and spatial equalization of the sound reproduction system.

Electronics, Computer, Telecommunications, Mechanical

Active Noise Cancellation

Research carried out in collaboration with ASK Industries, Reggio Emilia. The purpose is to design and build a prototype of device, based on DSP, for processing in real time the signal captured by a primary microphone. The filtered signal is output from one or more loudspeakers, creating an antiphase sound field that cancels the original noise. The student must possess the ability to program a DSP (also using high-level interfaces such as "block diagram"), to carry out measurements of impulse response (Aurora) and of spectra (SpectraRTA), and also to work in the workshop in order to build the mechanical components of the device.

Mechanics, Electronics, Computer Science, Information Technology

Analysis of sound quality of bakery products

Research carried out in collaboration with Barilla, Parma. The purpose is the analysis and optimization of the sound created during fracture and / or chewing of bakery products (such as cookies, biscuits, crackers, sticks, etc..). Binaural recordings are employed for objective analysis of the sound produced, and tests with human subjects are performed, in order to operate a collection of questionnaires and obtain an analysis of the subjective sensations evoked while eating these products. 

Mechanics, Mechanical Engineering for the Food Industry, Information Technology, Management

Use of ultrasound in the food industry

Research carried out in collaboration with Barilla, Parma. The goal is to  evaluate the possibility of using a treatment section with ultrasound for sanitizing and / or homogenization of liquid foods, either as a single treatment, or as a treatment subsidiary to other devices. The student must work alongside a research assistant in carrying out experiments on the pilot line and in the analysis of results.

Mechanics, Mechanical Engineering for the Food Industry

Noise analysis of gear pumps

Research carried out in collaboration with Casappa, Parma. The purpose is to develop new methods of signal analysis, applicable to both the noise signal radiated during operation of gear pumps, and to the "pressure ripple" signal detectable in the delivery circuit of the pump. It is expected to obtain useful information in order to identify problems in the pump (diagnostics), and to develop new, more silent pumps and of longer duration.

Mechanical, Electronics

Analysis of the sound generated by old gramophones and radios

Research carried out in collaboration with the House of Sound, Parma. It deals with measuring the sound characteristics of old gramophones or receivers radio, part of the famous Patane' collection. The recordings could be used as such in the exhibition of the House of Sound, or even be "virtualized" making use of advanced techniques of analysis and resynthesis available in the laboratory of virtual reproduction of the House of Sound.

Telecommunications, Computer Science.

Sound reproduction using loudspeaker arrays

Research carried out in collaboration with the House of Sound, Parma. The student will have to create recordings or compositions, mostly of musical events, but also of "special effects", to play on the WFS playback systems available at the House of Sound: the WFS "white room" the "Sonic Chandelier". The student must first acquire an adequate understanding of the physical mechanisms underlying the Wave Field Synthesis, and master the system hardware and software that operate the House of Sound. Then he must create one or more "documentary soundtracks" that will be "projected" at the House of Sound.

Telecommunications, Electronics, Computer Science

Shooting techniques with virtual microphones

Research carried out in collaboration with the RAI Research Centre, Turin. The purpose is the development of a device for recording "live" events such as concerts, sporting events, theatre, etc.., in all cases in which microphones located close the sound sources cannot be employed. The microphone arrays employed are the Holophone and the Eigenmike 32. The student must make a series of test recordings with these devices, process the traces recorded so as to synthesize an adequate number of virtual microphones with suitable directivity and pointing, and manage the organization of special "surround" listening tests with trained listeners specialize, with the goal to identify the best signal processing technique.

Telecommunications, Electronics, Computer

Three-dimensional measurement of impulse responses in theatres and concert halls

Research carried out in collaboration with AIDA Srl, Parma. The purpose is to develop a method of measuring acoustic characteristics of a room, making use of a new portable recording system, equipped with a tetrahedral microphone probe, called Brahma. The student must perform measurements with the "exponential sine sweep" technique in a number of rooms, comparing the results of the new technique with the traditional ones, and employing the results for designing suitable acoustical corrections, when required.

Electronics, Civil, Telecommunications

Porting of Aurora plugins under Audacity

 

The project, recently launched thanks to the activity of research assistant Simone Campanini, aims to rebuild the suite of Aurora plugins ( www.aurora-plugins.com ) as add-on modules for the open-source and cross-platform program Audacity .
The student will have the opportunity to participate in the development of new software modules, operating on the platform of choice (Windows, Mac, Linux) and to test the correct functionality by performing experiments of measurement and listening, and by comparison with the current implementation for Adobe Audition, and with cutting-edge laboratory instrumentation (Audio Precision, Bruel & Kjaer, etc..).

IT & Computer Science Telecommunications, Electronics

Porting of Aurora and X-volver plugins to VST format

 

The project, recently launched thanks to the activity of research assistant Andrea Venturi, aims to rebuild the suite of Aurora plugins (www.aurora-plugins.com ) as additional modules in VST format.
The student will have the opportunity' to participate in the development of new software modules, operating on the platform of choice (Windows, Mac, Linux) and to test the correct functionality by performing experiments of measuring and listening, and by comparison with the current implementation for Adobe Audition, and with cutting-edge laboratory instrumentation (Audio Precision, Bruel & Kjaer, etc..).

IT & Computer Science, Telecommunications, Electronics

Non-destructive analysis of frescoes by acoustic and vibration measurements

Research sponsored by the Cariparma Foundation, Parma. The purpose is to develop a new test method with very small invasiveness, aimed at locating structurally degraded areas in plaster, frescoes, mosaics, and other structures of historical value. The new method makes use of an "exponential sine sweep" signal, in order to operate with very low sound pressure level; an array of loudspeakers focuses sound waves, so that just a restricted area of the surface to be scanned is stressed, and an array of microphones (or a Laser-Doppler velocimeter) is employed in order to determine the vibrational response of a single point of the structure. The student must first operate a verification of the new method on artificial samples in laboratory, and then perform experimental tests "in situ" inside churches and other historic buildings in Parma.

Civil, Mechanical

Development of a sonar system for "sub-bottom profiling"

Research carried out in collaboration with WASS, La Spezia and Livorno. The goal is the development of a low-frequency Sonar system, operating in the audio field (1000-20000 Hz), broadband, in order to obtain a good penetration into the seabed and to view the soil stratigraphy below. The system uses an array of 16 hydrophones and an underwater loudspeaker fed with sine sweep signal. The student will have to make a series of tests in the laboratory, in the test tank and in the sea, in order to validate the operation of the system, and to process the results of the acquired traces in order to obtain three-dimensional images of the stratigraphy of the bottom.

Electronics, Environment and Territory, Computer

Development of a three-dimensional underwater sound recording system

Research carried out in collaboration with AIDA Srl , Parma. The purpose of the research is the development of a device for recording underwater the signals of 4 hydrophones, capable to determine the direction of origin of the sound, to be used for underwater environmental monitoring in marine protected areas. The student must follow the electromechanical development of the prototype and carry out the characterization of performance with in-tank testing and in-sea testing.

Electronics, Environment and Territory, Computer Science, Mechanical Engineering

Development of an "Acoustic Camera" system

Research carried out in collaboration with AIDA srl , Parma. The purpose is to reactivate the "Acoustic Camera" system that was built four years ago, making use of high quality microphones and of a new portable hardware acquisition system, which should allow to be used outside the laboratory. The student must first reassemble the system and make it operational, then verify its performances through a series of measurements to be carried out both in the laboratory, and in industrial environment. If versed in programming, the student may also participate in the development of the new real timea software, that should replace the existing Matlab software, currently capable of "off line " processing only.

Mechanical, Civil, Electronics, Computer Science

Mapping of environmental noise through measurements and simulation

Research carried out in collaboration with the Municipality of Parma, Department of Environment. It is aimed to realize a first prototype of a control unit for acoustic monitoring of urban areas, based on the assembly of already existing, low cost components. The student must make a series of surveys by placing these 10 units in the hot spots of the city, in order to achieve the noise map in the city of Parma, also making use of the simulation software Citymap.

Environment and Territory, Civil

Development of a "low cost" measurement system for building acoustic

Research carried out in collaboration with AIDA srl , Parma. This is to verify the ability to employ low-cost instrumentation, making use of digital audio equipment originally developed in the field of music, to carry out building acoustics measurements, thanks to recent technical rules which allow for the use of the exponential sine sweep signal. This makes it possible to use a small loudspeaker and low-cost digital audio recorders. The student must carry out a campaign of comparative measurements, using either the new method and the traditional one, and compare the results obtained in a number of civil and public buildings (school, hospital, etc..).

Civil, Environment and Territory


Copyright (C) Angelo Farina - reproduction prohibited without permission.
Last revised: 02/12/12, 16:02