I'm just curious, how wide (relative to wavelength) must an aperture be for 100% (or near 100%) of a sound wave to pass through it? F. Alton Everest specifically stated in the Master Handbook of Acoustics that if 13% of a thick steel wall was free (ie holes/slits) then 97% of the energy would pass through...Is this wavelength specific or universal to all wavelengths relative to the aperture?
Think of it like this
____ ____ ____ (3 4" obstacles with 2 .5" apertures, a 1700hz wave (~8") would easily diffuse around the 4" obstacle, but is the opening large enough for the 1700hz wave to pass through?)
for reference, the sound waves wavelength must exceed the fundamental baffle width (wavelength>baffle width) before the 2pi to 4pi transition can occur