Advanced acoustics
Overall Course Objectives
The course objective is to enable the student to analyze complex sound fields using analytical, numerical and experimental tools, as well as signal processing methods in acoustics.
We study sound fields in rooms (modal, statistical, and numerical approaches), wave guides (ducts, musical instruments, headphones) and sound radiation from acoustic sources. We also study microphone array measurements and signal processing (beamforming and acoustic holography), spatial sound, sound field reproduction, and Machine Learning in acoustics. The course aims at providing a deep understanding of acoustic phenomena and methods that are central to modern acoustic engineering.
The course combines analytical and hands-on experimental activities, with weekly laboratory measurement sessions. There are also a number of guest lectures from researchers, PhDs and industry.
See course description in Danish
Learning Objectives
- Analyze the sound field inside a duct at low frequencies, design silencer systems and characterize sound in waveguides, such as headphones or wind instruments.
- Examine the sound field inside a duct, derive the Green’s function and explain the propagation of sound inside it.
- Analyze the sound field in a room based on the modal theory. Derive the Green’s function in a room and use it to explain the central acoustic processes that occur in a room.
- Examine the sound field in a room based on statistical wave models, and how these methods are used in practical applications of room acoustics.
- Analyze and interpret the decay of sound in a room, based on the modal and statistical theories.
- Examine a sound field based on its active and reactive intensity, and evaluate the usefulness and limitations of intensity measurement.
- Describe the radiation from point sources, and how coherent sources affect each other.
- Interpret the expression for the sound field radiated by a spherical source. Illustrate the use of spherical harmonic expansions for sound radiation and scattering.
- Analyze the sound field radiated by a planar source, using space domain and wave number domain formulations.
- Illustrate the fundamentals of microphone array methods (beamforming and acoustic holography). Describe how these methods are used to analyze sound fields
- Apply Machine Learning and Deep Learning models to problems in acoustics
Course Content
Plane waves and higher-order modes in ducts. The modal theory of room acoustics; statistical room acoustics. Measurement of sound intensity flows. Numerical acoustics (finite element and boundary element methods). Radiation of sound from acoustic sources. Scattering of sound. Introduction to acoustic holography and beamforming. Spatial sound, sound field reproduction with loudspeaker arrays and Machine Learning in acoustics.
Recommended prerequisites
34840, Fundamentals of acoustics and noise control
Basic signal processing
Teaching Method
Lectures, problem solving, project work (laboratory exercises, MATLAB simulations and finite element calculations).
Faculty
Remarks
The course is a natural introduction to master thesis work.
E-learning is used in the form of chat room, web-based tools og other on-line ressources.