DIY SkyLine

mtl777 · Post by **mtl777** » Fri Oct 29, 2004 7:25 am

I want to make my own SkyLine diffuser similar to RPG's:

http://www.rpginc.com/products/skyline/index.htm

RPG's product is made of polystyrene foam. I am planning to use 2" thick AP foil-faced foam from Johns Manville:

http://www.jm.com/insulation/building_i ... lfaced.pdf

Do you think this kind of foam will work? Too bad they don't have acoustical data on this, but I know that it's lightweight and porous, it would shed fine powder if you scratched it.

Thanks,

Mitch

lowdbrent · Post by **lowdbrent** » Sun Nov 07, 2004 7:06 am

You can use whatever you like for the most part. The purpose of the RPG SkyLine is diffusing not absorbing waves. Since the frequencies sacttered are higher, it really makes no difference if it is wook or plastic.

Unless you purchase a skyline and analyze it, you will not be successful. The SkyLine was designed and built by math. Each of those blocks is placed a specific height for a reason.

AndrewMc · Post by **AndrewMc** » Tue Nov 09, 2004 6:32 am

One of the BBC research papers has the exact design of the rpg skyline.

AVare · Post by **AVare** » Tue Nov 09, 2004 7:44 am

AndrewMc wrote:One of the BBC research papers has the exact design of the rpg skyline.

Do you mean this one?

http://www.bbc.co.uk/rd/pubs/reports/1995-01.pdf

Sly Andre

dymaxian · Post by **dymaxian** » Tue Nov 09, 2004 12:33 pm

No, but close - there's one that has the exact layout set out. It's around here somewhere.

BTW double check the flammability of this stuff. Polystyrene will burn faster than you can imagine, and if it's on the ceiling you will literally have napalm waiting to happen over your head. If I had poly insulation on my walls, I wouldn't even let people burn incense in my studio.

Good luck!

dymaxian · Post by **dymaxian** » Tue Nov 09, 2004 12:36 pm

This is the BBC paper you meant

http://www.bbc.co.uk/rd/pubs/reports/1990-15.pdf

There's a link all about home-made skyline diffusors here

http://www.johnlsayers.com/phpBB2/viewtopic.php?t=326

AVare · Post by **AVare** » Tue Nov 09, 2004 1:19 pm

This is the BBC paper you meant

Thanks Kase!

Andre

dymaxian · Post by **dymaxian** » Wed Nov 10, 2004 1:37 am

BTW, as they mention in a few other threads, those BBC papers are literally a gold-mine of information. These guys have been studying acoustics for far too long for their data to be ignored. They should be required reading for folks on this thread, even if a great amount of their research is about larger studios and control rooms that the people around here could only dream about building. These guys came up with a lot of the numbers and research that the guys at Auralex and RPG use to design their stuff. And it's out there for free!

The more knowledge you have at your disposal, the more dangerous you are. *snicker*

Pertaining to this thread, pay special attention to the line where they tested a group of these diffusors together in a 4x4 array and it actually HURT the performance, and another line where they mention that they did not run tests close to this diffusor, only far-field tests. They speculate that sound sources or listening positions closer to the diffusor will most likely have a much different effect.