Learning outcomes of the course unit
The objective of this course is to introduce the fundamentals of a broad variety of topics related to acoustics, with a balanced combination of theory, experimental measurements, numerical simulations and computer programming.
Students who will successfully complete this module will be able:
- To explain the theoretical fundamentals of a number of topics related to acoustics, as listed in the extended programme above
- To understand and be able to use the technical language used in scientific literature of acoustics
- To apply engineering acoustic knowledge and calculation formulae to the solution of a number of simple acoustic problems
- To design and to apply a number of signal processing algorithms to acoustic and audio signals (using MATLAB)
- To use (at a basic level) a number of commercial software packages for acoustic simulations and signal processing
- To perform some acoustic measurements
- To interpret results of acoustics measurements and of plots and graphs related to acoustic phenomena
Course contents summary
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.
Because of its multidisciplinary nature, the Course of Applied Acoustics is attended by students from various degree programs (almost all branches of Engineering, but also some Architecture students).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.
Definition of quantities. Propagation of mechanical disturbances in an elastic medium.
Sound pressure and particle velocity. The speed of sound.
The wave equation.
Sound intensity and sound energy density. Active and reactive intensity. Propagating and stationary sound fields.
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.
Masking phenomena in time and in frequency. Audio compression algorithms based on psychoacoustic principles.
Plane waves, spherical waves, standing waves. Sound reflection and absorption.
Sound propagation outdoor.
Room acoustics: reverberation, sound quality in concert halls and opera houses, ISO3382 acoustical parameters.
Advanced methods for impulse response measurement.
Digital Signal Processing applied to audio and acoustics.
Fundamentals of spectral analysis and Fourier transform.
Sampling of signals.
The DFT and the FFT algorithms. Convolution.
FIR and IIR filters, calculation of Inverse numerical filters.
Active control of sound.
Virtual acoustics and 3D audio.
Electroacoustics and instrumentation for acoustic measurements:
Acoustic transducers (microphones, loudspeakers).
Devices for processing analog and digital acoustic signals: amplifiers, equalizers, reverbs, compressors, etc...
Sound level meters, spectrum analysers, impulse response measurement systems.
Virtual Instrumentation on PC and software for acoustical measurements, with practical exercises in the laboratory.
Techniques for numerical simulation of sound propagation:
Fundamental of finite element methods, boundary element methods, and ray tracing.
The recommended textbooks for an introduction to this topic are:
P. Fausti: Acustica in Edilizia , Rockwool, Italy, Milan, 2005 (free download in PDF format)
R. Spagnolo: Acustica: Fondamenti e applicazioni, UTET Università, 2015, ISBN: 9788860084460
T. D. Rossing (ed.): Springer Handbook of Acoustics, Springer Science+Business Media, New York, 2007
L.E. Kinsler, A.R. Frey, A.B. Coppens, and J.V. Sanders: Fundamentals of Acoustics, Wiley & Sons, 2000
F. Fahy: Foundations of Engineering Acoustics, Academic Press, 2000,
The course includes a combination of frontal lectures and workshop/laboratories.
The theoretical background of the material covered by this module will be explained during frontal lectures. Computer-based and practical demonstrations will often be used during lectures to demonstrate the practical aspects of this discipline.
Hands-on workshop or laboratories, with the aid of computers or measurement equipment, will also be carried out to allow students to familiarise themselves with numerical simulations and signal processing and with experimental measurements.
Class tests will be carried as formative or summative assessment to monitor and evaluate student progress.
Assessment methods and criteria
The assessment consists of two separate tests:
1) a written examination, consisting of a number of exercises. Some students may be exempted from the written test, on the basis of the results obtained during in-class tests.
2) Oral examination, which focuses mainly on theoretical topics, and which can be accessed only after passing the written test.