1. Properties of traveling waves: Acoustics applications
Physics of Music, Spring 2018

2. Wave Mechanics: Acoustic Applications
traveling wave transverse wave longitudinal wave plane waves circular waves velocity frequency wavelength Law of Reflection parallel walls curved surfaces Diffraction

3. Law of reflection qi = qr
Angles measured with respect to the normal (dashed line perpendicular to the surface)
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4. Plane Wave Reflection and Ray Diagrams
normal
Ray diagram
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5. Hocus Focus! Reflection from concave surface
Image source: (left); Berg and Stork, Physics of Sound, 3rd ed. (right)

6. Applications of Reflection
Image source: D. Hall, Musical Acoustics (left)

7. More reflection applications
Disney Concert Hall, Los Angeles

8. Parallel walls: resonance frequencies
1-D resonance frequencies
Vienna Musikverein “shoebox”
3-D resonance frequencies

9. Diffraction Narrow aperture Wide aperture
Tendency for waves to spread out as a result of passing by an edge (barrier or passing through a slit)
Wide aperture
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10. Diffraction Patterns Diffraction in ripple tank
Diffraction on a MUCH larger scale (Channel Islands, CA)
Image sources: (top)
Bottom:

11. Diffraction in Action

12. Huygen’s Principle Wavefront = many wavelets spherically spreading out
Plane  circular (diffraction!)
Wavefront = many wavelets spherically spreading out
Image sources:
(left and middle) Berg and Stork, Physics of Sound, 3rd ed.
(right) UC Irvine Optics research group.