Reflection, Refraction, and Diffraction

1. Reflection, Refraction, and Diffraction

2. Quiz 2 • For a oint sound source , If you measure a sound level I1 = 60 dB at distance d1 = 3 m then at distance d2 = 5 m the inverse square law predicts a sound levelI2 = dB

3. The answer:

4. Reflection, Refraction, absorption, and Diffraction

5. Diffraction

6. Diffraction

7. Difusion

8. Sound Reflection

9. The Law of Reflection • The law of reflection states that when a ray of light reflects off a surface, the angle of incidence is equal to the angle of reflection.

10. Early First-Reflected Sound

11. Curved Reflectors If a curved surface is used to reflect waves, they can be focused onto a point. The diagrams below show both a spherical and parabolic mirror shape

14. Reflection material

15. Ray tracing diagram

17. Oblique reflector:

19. Non-plane reflector

21. Acoustical device design • Limit of perceptibility: حد الإدراك • SB+BE-SE ≤17m يتم تصميم العواكس بحيث لا يتجاوز فرق المسار بين الصوت المباشر والصوت المنعكس حد الإدراك

22. X › 4λ If , λ1000Hz =34cm, Then the reflected surface have not be less than : 4λ=136cm

23. Echo of sound1- corner echo

24. Focusing echo

25. Sound shading

26. Acoustic shadow