Originally Posted by Lonely Raven
... I could design a diffuser that works from 272Hz to 13kHz. But it would be 12" deep, and roughly 36" X 36" with 1" wide wells. Being realistic. lets look at 6"-8" deep, 1"-2" wide wells. 24" X 24" - something like what I built for my ceiling, but deeper.
Do we really need them to work that low?
Unless the speakers are huge, those freq are more or less omnidirectional.
But that raises a question I've never considered - what effect does diffusion have on room modes? Though I guess the 300 Hz range is around where they stop being an issue.
Originally Posted by bwaslo
I had a book shelf in my room (before clearing it out to make the house ready for showing according to realtor!) that actually had a very noticeable diffusing effect. ... It might have been a case of "better than nothing" maybe, but quite effective subjectively.
How did you determine the benefit was from diffusion, as opposed to absorption or interfering with a first reflection that might have been problematic?
Re the charcoal, most interesting.
I just read a little from the links, but it sounds like it works by essentially "solidifying" (adsorbing means they stick to the surface of the carbon) some of the air molecules so that they don't contribute to gas pressure.
What I don't understand is how that would work on both halves of the compression/rarefaction cycle.
I can see how pressure increase would be reduced by the molecules being impressed into the carbon surface, bur what about rarefaction?
Ah, it must be that at atmospheric pressure there is a portion of adsorbed air,some of which is released on rarefaction.