I am still trying to get my head wrapped around how hangers work.
They act mostly like acoustic waveguides, as well as impedance tubes, and also with some standing-wave resonance going on between the panels.
What woul happen if you hung panels of rigid fiberglass without the homosote core?
Then there would be no wave-guide action, and no resonance action, and no impedance tube action. So they would just be plain old porous absorbers.
Or: hang alternating panels of homosote and rigid fiberglass.
That would act somewhat like an undamped wave-guide with baffles in between, and since pure absorptive baffles aren't much good at low frequencies when separated by large distance, the effect would likely be very much reduced.
It's not so much that I want to try to do it different, but to understand what the various components do.
The Homoste guides the waves, re-directing them towards the rear wall at a high angle, where there is thick absorption, plus the absorption on the panels also attenuates. The impedance tube effect provides good absorption at certain specific frequencies, and the standing wave effect provides some absorption (or amplification!) at other specific frequencies that are not necessarily related to the frequencies of the other effects. The width of the panels controls the main absorption effect, the distance between them controls the standing wave effect, and the thickness of absorption on the back wall controls the overall absorption from the wave-guide effect.
- Stuart -