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Old 2006-01-30, 18:16
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jaxadam jaxadam is offline
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Join Date: Oct 2004
Location: Jacksonville, FL
Posts: 147
Quote:
Originally Posted by johnmansley
Volume - or loudness - is subjective and related to three things:

1. The energy of the vibrating source.
2. The condition of the medium through which it propagates.
3. The distance involved.

The energy of a soundwave is related to its amplitude such that soundwaves with large amplitudes possess higher energy than those with smaller amplitudes.

Now, constructive interference occurs when the peaks or troughs of two distinct waves travelling in opposite directions coincide. The net effect of such an occurrence is that the amplitude of the newly combined wave is twice that of the original waves, resulting in greater energy.



Constructive interference does not necessarily have two do with two waves traveling in opposite directions. The peaks don't even necessarily have to even line up, since all interference is is a superposition of different waveforms.

You can have two different waveforms of different frequencies construct or destruct. For my job, I deal with seismic wave propogation in earth, and we have cases where we will have one waveform accelerate another, both having different frequencies, and they will interfere. Our goal is to time these things so they DESTRUCT, to reduce vibrations (to make the Army Corps of Engineers happy!).

Although I am very impressed at how much you guys know about this stuff!
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