Natural Science Forum / Physics / Acoustics / May 2005

When I did some business in West Virginia a "solution" they referred to as
"mountain law" was mentioned more than once.   :-)

In view of the concern about other neighbors, do you really want to throw
back the sound (amplified)?  Or, would you rather work on cancelling the
noise at your end?  (You may have the same set of issues either way).

Assuming that the frequencies from the truck are relatively low, or at least
that most of the energy is at lower frequencies, then maybe a noise
cancellation method would work for you.
In principle, it goes like this:

Put a speaker or speakers at the edge of your property between your house
and the normal location of the truck.  I think the closer to the truck the
better - but that's a guess really.  Note that speakers can be susceptible
to damage from high velocity projectiles or high-mass, low velocity
projectiles.  So, maybe place them behind a berm.

Drive the speakers so that the sound received at your house is minimized.
Don't expect to get rid of broadband noise this way (sounds like air
escaping from a compressor hose aren't likely to be reduced).  Engine noise
may well be reduced though.
The simplest method that puts speakers "between your head and the truck" are
noise cancelling headphones.

You put a microphone where you are, process the microphone output to drive
the speakers.  Google on Automatic Noise Cancellation and Adaptive
Filtering.

Fred