My take on loud pipes is that they're often so loud that they reverberate extremely much in settings where it's the most counterproductive: The city. Combine this with other people (besides me) not being to tell where it's from either, or the distance, and you have a lot of cagers trying to find out where it's coming from and how far away it is.
Oh, yeah, and higher frequency sound is directional, where low frequency sound is omnidirectional. That's why it matters that the tweeter in your speaker points towards your ears, whereas the low frequency signals can come from a subwoofer placed in the corner of your living room.
It's not something that is new or weird, it's pretty basic science about audio wave propagation.
You don't need to be an elephant to be able to hear this either: Get a speaker with a tweeter so you know for a fact that the higher frequencies comes out, poke your head close to it, at the right height. Then begin move your head down, up, or to the sides, away from the tweeter. You will notice, that as you move away (to the sides, up, or down) that the audio will become much more bass-heavy, as if it's cutting away the treble. The reason for this is that you actually are cutting away the treble by moving out of reach of the "beam".
Twoupfront screwed with this post 09-13-2013 at 08:06 AM
Reason: spelling etc.