Intensity of sound behind a sphere

Click For Summary

Discussion Overview

The discussion revolves around the intensity of sound waves as they interact with a spherical object, specifically focusing on how sound diffracts around the sphere and the intensity at various points on its surface. The scope includes theoretical analysis and potential applications in sound propagation and recording techniques.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant inquires about the intensity of sound at a point on a sphere opposite a sound source, seeking a formula for intensity at any point on the sphere.
  • Another participant notes the complexity of calculating intensity at all points due to the sound source being directly visible from only half the sphere, suggesting that intensity is inversely proportional to the square of the distance from the source for directly incident sound.
  • A different participant expresses interest in the indirect half of the sphere and asks for a formula to calculate the intensity of sound after diffraction around the sphere, assuming no reflected sound waves.
  • Reference is made to Rayleigh's Theory of Sound, which discusses sound propagation in the presence of a spherical obstacle, though it is acknowledged to be complex.
  • One participant suggests looking into "head related transfer functions" and "dummy head" binaural sound recording techniques as potentially relevant areas for more recent information, while noting that simplicity may not be guaranteed.

Areas of Agreement / Disagreement

Participants express differing views on the feasibility of calculating sound intensity at various points on the sphere, with some focusing on direct sound and others on diffraction. The discussion remains unresolved regarding the specific formulas or methods applicable to the scenario.

Contextual Notes

Limitations include the complexity of sound diffraction around spherical objects and the assumptions made about the absence of reflected sound waves. The discussion also highlights the potential need for more accessible theoretical frameworks compared to classical theories.

5skin
Messages
2
Reaction score
0
If I have a sphere with radius r, a distance d away from a sound source of intensity I0. What will the intensity I of the sound wave be on the point of the sphere directly opposite the source? Preferably I would like to find the intensity of the wave at any point on the sphere.
 
Physics news on Phys.org
Any point would be difficult, because the sound source is "directly visible" from half the sphere at most. Other points can be reached only indirectly, and the overall analysis becomes very complex.

For the sound that is directly incident, the intensity is inversely proportional to the square of the distance from the source.
 
I'm only concerned with the indirect half of the sphere. I want to know how to figure out the intensity of sound after it has diffracted around an object. I'm also assuming that there are no reflected sound waves. Is there any formula to calculate the intensity of a diffracted sound wave around a sphere?
 
Rayleigh's Theory of Sound had a section on sound propagation in the presence of a spherical obstacle. But that was anything but simple. I do not know whether there is a more recent and simpler exposure. I would guess there could also be studies on the diffraction of light by spherical bodies, I think their results could be adapted.
 
voko said:
I do not know whether there is a more recent and simpler exposure.

You might get some information by looking up the math of "head related transfer functions" - i.e the methods used in video games etc to convert sound coming from an arbitrary point in space, into the two inputs at your ears.

Or, see if there is any theory relating to "dummy head" binaural sound recording techniques.

More recent than Rayleigh - yes. Simpler - not necessarily!
 

Similar threads

  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 11 ·
Replies
11
Views
6K
  • · Replies 82 ·
3
Replies
82
Views
8K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 28 ·
Replies
28
Views
3K
  • · Replies 7 ·
Replies
7
Views
3K
  • · Replies 14 ·
Replies
14
Views
3K
  • · Replies 58 ·
2
Replies
58
Views
4K
  • · Replies 9 ·
Replies
9
Views
4K