Let's say I have an infinite line source in 3d wave medium, like a pulsating cylinder, emitting a broadband noisy signal. I know that the pressure falls off at 3 dB per doubling in distance, unlike a point source which falls off at 6 dB per doubling in distance, because the cylindrical wavefront is only spreading out along one direction.
But I am unclear on whether this has a frequency-dependent effect, and on the relationship of this situation to the http://en.wikipedia.org/wiki/Stationary_phase_approximation.
Is the signal received by a listener some distance from the line frequency-dependent? Does it roll-off at high frequencies?? And am I posting at the wrong site?