1. John Laurence Davy RMIT University Melbourne, Australia
The directivity of the forced radiation of sound from panels and openings including the shadow zone
John Laurence Davy
RMIT University
Melbourne, Australia

2. Situation of panel or opening
From room to outside via opening or panel in (baffled) wall of room
From outside to room via opening or panel in (baffled) wall of room
From duct to outside via (baffled) duct end opening
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3. Directivity in infinite baffle
Transmitted sound
Finite opening or panel of length 2a θ
Infinite baffle φ
Incident sound
Normal
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4. Directivity effect of finite width
ka = 15
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5. Radiation efficiency
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6. Diffraction due to finite baffle
Sound
Sound
Normal
Normal θ θ
Rigid baffle length 2L
Rigid baffle length 2L
Sound incident on baffle
Sound radiated from baffle
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7. Sound pressure doubling
kL = 10
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8. Small baffles at normal incidence
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9. Interpolation region p(90) = 1 p(0) p(90) = 1
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10. Sound incident at angle 
b m 
g m
Sound source
b tan  m
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11. Incident sound intensity
α = 0.3, b = 2 m, g = 4 m
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12. Directivity of duct sound source
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13. Diffraction into the shadow zone
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14. 6 mm glass 60 degrees
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15. 85 mm diameter duct 120°
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16. Conclusion
The directivity of panels and openings excited by sound incident from the other side can be predicted using the model presented in this paper
This two dimensional model agrees well with experimental results for both panels and openings
The simple diffraction model and the angular weighting model work well
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