Good one!
I have to remember that whey trying to explain pattern control.
Here is another way to "look" at it.
Go to the ocean and find a pier.
Notice how there are basically 2 sizes of waves. The obvious large ones (caused by the tide), and the smaller ripples (caused by the wind).
The large ones are low freq and the small ones high freq.
Now look at the area around one of the pilings on the pier.
Notice how on the opposite side that the wind is blowing, there is a calm area (in respect to the small waves) behind the piling, where it is being shadowed.
The piling is large in respect to the size of the wind waves.
But ALSO notice that the large wave is completely unaffected by the piling. It is still the same size and shape
It takes something MUCH larger to control or affect the larger wave. A large barrier -in respect to the size of the wave.
As it is in audio, the larger the wave (lower the freq) the more "stuff" it takes to either control or affect it.
This goes for either pattern control or acoustic treatment.
DO NOT expect to put some fuzz on the wall and control low freq.
It takes SIZE. So the best you can hope to do is to "break it up" rather than absorb it.
Once you start to think about sound in terms of wavelength SIZE, all sorts of things start to "come together".
Don't think freq, think SIZE OF THE WAVEFORM.
Go out in your drive wave and draw a single cycle of a 50Hz (or better yet a 20Hz) wave to get an idea of how LARGE we are talking about.
For those who don't want to do the simple math, 50Hz is roughly 22 feet for a single cycle and 20Hz is roughly 56 feet-for a single cycle.
And 10 Khz is less than an inch That is easy to draw and control
YES SIZE MATTERS