only my experience of it as a musician. For instance, when I was thinking of making myself a didgeridoo out of a PVC pipe, a mathematically-inclined friend told me that if I told him the diameter of the tube and the note I wanted it to produce, he'd be able to calculate the length the tube would need to be to accomplish that. And a wider tube would produce lower notes at the same length because of bigger volume and the way sound waves are produced and shaped in there.
But you're the audio guy so correct me if I'm wrong. =)