Sorry, I started answering this 45 minutes ago but a truck showed up with another pallet load of No Rez that I had to go unload.
I like No Rez but find it overpriced. Anyone have a substitute?
I thought it was cheap for what it does verses the cost and time of alternatives.
The Sonic Barrier from the link above is just a sheet of foam with no damper. It really does nothing other than absorb internal standing waves in the box. If you have a resonant panel, it's worthless.
There are other products that are advertised to be like it but are not, and can make things worse in some areas. Whisper Mate for instance is one to avoid.
You can add mass and weight with various material and it is best that you use something with a different resonance frequency than MDF. Adding more MDF or material like what was posted lessons the resonance some but also shifts it to a higher frequency. So instead of a bass resonance you get a slight mid-range resonance. So some type of damper is still recommended.
The best DIY thing to do is to add a sand layer. See this thread:
http://www.audiocircle.com/index.php?topic=53675.0Resonances are simply not transmitted well (at all) through sand. Unfortunately this is not a solution for an already built box.
The next best DIY method is to buy industrial floor tiles from Lowe's or Home Depot. It is a little over 1/8" thick and just under a dollar for a square foot (one tile).
You can cut it with a box cutting knife to the needed size. Then use contact cement to bond it to the inside of the box. Be sure to be outside when doing this as the fumes are pretty heavy from contact cement. Most other alteratives (glues) require pressure until dry.
Then go to a fabric store of some kind and get some open cell foam. If you want you can even order the Sonic Barrier foam from PE. It is more expensive than most open cell foam in the fabric stores and you have to pay a heavy shipping fee as it takes up a lot of volume (not heavy). You might like that alternative though better than driving around town and shopping for a good dense fabric foam.
Okay then you have to cut it into the right sized pieces and bond it in with contact cement. Again watch the fumes. At least it cuts pretty well but can be slow going with scissors or razor knifes.
In the end the DIY stuff is about 70 to 80% as good as No Rez. And if your time is not worth anything then you saved a few bucks.
No Rez of coarse cuts easy on a table saw and the peal and stick pressure sensitive adhesive makes it pretty easy to install. I'll continue to brace well and use No Rez.
There you have it.
