Physical acoustics overview

In order to study the spatial properties of audio we need to know what is sound and how it behaves in space: how it propagates, what energy it does carry, how it does interact with other sound sources.

The first lecture of the course is therefore a 2h introduction to acoustics, and therefore it is a summary of what you already know from previous acoustics courses:

The topics we will treat will be:

  1. Waves on the air
    • The wave equation
    • Plane waves
    • Spherical waves
    • Energy and intensity
    • Decibel scale
  2. Features of the acoustic field
    • Frequencies and energies
    • Coherence and incoherence. Interference
    • Reflexion and reverberation
  3. Waves in a room
    • Room modes and geometric acoustics
    • The impulse response: direct sound, early reflections, reverberation
    • Reverberation time
    • Diffuse sound field
  4. Green function method
    • Wave equation in presence of sources
    • Diffraction and the Huygens principle
    • Green function in the free field

As references, any good acoustics book will do, like Kinsler‘s book, or even basic physics textbooks such as the one by Tipler. You can also check your lecture notes for previous courses.

Longitudinal wave traveling through a material medium. Extracted from Dan Roussell’s Acoustics and Vibration Animations

Also you can get good acoustics simulations in Dan Roussell’s Acoustics and Vibrations Animations web page. See in particular the following animations:

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Physical acoustics overview

It’s obvious: if the course is about 3D audio, it deals about sound, and we need to know what is sound and how it behaves: how it propagates, what energy it does carry, how it does interact with other sound sources.

The first lecture of the course is therefore a 2h introduction to acoustics, and therefore it is a summary of what you already know from previous acoustics courses:

The topics we will treat will be:

  1. Waves on the air
    • The wave equation
    • Plane waves
    • Spherical waves
    • Energy and intensity
    • Decibel scale
  2. Features of the acoustic field
    • Frequencies and energies
    • Coherence and incoherence. Interference
    • Reflexion law.
  3. Green function method
    • Wave equation in presence of sources
    • Diffraction and the Huygens principle
    • Green function in the free field

As references, any good acoustics book will do, like Kinsler‘s book, or even basic physics textbooks such as the one by Tipler. You can even search for good information in the Wikipedia.

Longitudinal wave traveling through a material medium. Extracted from Dan Roussell’s Acoustics and Vibration Animations

Also you can get good acoustics simulations in Dan Roussell’s Acoustics and Vibrations Animations web page. See in particular the following animations: