Sound Interference Experiment: Explaining Intensity Increase

[jaumzaum]

I cannot understand the following:

Imagine you have 2 sound sources and build up an interference experiment, where far away from the sources you have a receptor. Imagine you put the receptor at the same distance from the sources. If you turn off one source the receptor will receive a sound of intensity I, if you turn both on the intensity will be 4I, why is that? I can understand that for the light experiment, as the intensity depends on the square of the electric field, but how can I expain that for the sound?

 

[Simon Bridge]

What is the relationship between intensity and amplitude for sound?

 

[jaumzaum]

I don't know :(
Is there a physical formula that relates the amplitude with the intensity?

 

[Simon Bridge]

Have you tried looking it up?
http://en.wikipedia.org/wiki/Sound_intensity
... the intensity of sound waves is proportional to the square of the amplitude - like with any waves.