The course gives the theoretical principles behind active control of sound fields. This includes the basic principles for feed-forward and feed-back systems and filter design. Various control algorithms are discussed and the techniques for adaptive systems are introduced. The emphasis is on the acoustical principles for control of sound field with special focus on the possibilities and limitations for practical applications.
|Exam:||Written and/or oral|
The course focuses on the following subjects:
- Fundamentals of signal processing and system analysis: Frequency analysis, linear systems, impulse response and frequency response functions, digital filters
- One-dimensional sound fields: One-dimensional sound fields (e.g. plane waves in ducts) with a primary and a secondary source, principles of a feedforward system, various control algorithms (cancellation of the sound pressure, minimization of radiated power, maximization of absorbed power etc), fixed and adaptice controllers, feedback system, local control of a sound field, stability criteria
- Three-dimensional sound fields: Active control of free-field radiation, control of monopole radiation and of radiation from extended sources, the Kirchhoff-Helmholtz integral equation, global control of sound fields in enclosures, local control of sound fields in enclosures.
The course also comprises in-class exercises and one lab exercise.
For the course syllabus (e.g. intended learning outcomes) please see the course page at Chalmers.
- Lecture notes (see course page)
- Nelson, P. A., Elliot, S. J., “Active Control of Sound”, Academic Press (1992)