Originally Posted by doublewing11
after paying big bucks for Quest treatments,
Manufactured tend to have some fireproofing and a reasonable balance between rigidity of material and weight.
But there's always DIY.
Polycylindricals are easy to make (e.g. four columns for your surrounds), and do debatably better than QRDs.
Most reverberation chambers and large music halls, which are required to have diffuse sound for their tests, use polys instead of QRDs.
Just make absolutely sure you don't make them all the same size/diameter, because you'll get lobbing which you don't want.
Here's a ceiling polysorberhttp://www.bobgolds.com/TrapTodd/home.htm
By combining room shape, with common materials such as a bunch of wooden blocks, or even stone, you can also get diffusion
This fella made his own out of Styrofoamhttp://www.bobgolds.com/DifuserKgveteran/home.htm
The RPG Skylines have been copied to one degree or another all over the place.
Technically the RPG ones are probably the best numerically -- to protect the numbers their patent application deliberately has a couple of wrong well depths. Nonetheless you could look up their patent application and use those numbers and not go wrong.
These numbers, for example, aren't as good, but they're probably almost as good.http://www.gearslutz.com/board/bass-traps-acoustic-panels-foam-etc/720982-diffusion-confusion.htmlhttps://www.youtube.com/watch?v=2e3jtqgTmEIhttps://www.youtube.com/watch?v=oHTmNyo_0O0
Blackbird Studio C took this to the extreme. Their ceiling diffuser pattern and depth is incredible. Its a very unusual space to work in acoustically.http://recording.de/uploads/newbb/50c8b5d59ca085cad2a02465fe27189a.jpghttp://download.sea-vertrieb.de/newsletterarchiv/2009/docs/blackbird_studio.jpghttp://1.bp.blogspot.com/-ocp29ygwcRs/UceRenIddfI/AAAAAAAABhw/po28GjEGfPI/s1600/IMG_3306.JPGhttps://www.youtube.com/watch?v=peCF0gwTWoE
[humor]I'm guessing since you're leaning towards MSR, you're not going to mini Blackbird[/humor]https://www.youtube.com/watch?v=PtpJtv5ngew
Some other graphs:
Essentially, diffusion is just bouncing the sound in multiple directions, to
a) reduce the dB of the first reflection, and
b) increase the complexity of the sound field, giving a feeling of spaciousness.
Sometimes, just letting a woman with a credit card loose in a room does wonders for diffusion, and high frequency absorption.
But she wouldn't do thishttps://www.youtube.com/watch?v=FOjHsexNBTQ#t=501