In reply to:

Wow, I wish I would have known about that stuff when I was finishing off my basement. Thanks for the link!



No problem. And the nice thing is that this stuff is not a heck of a lot more expensive than your typical pink insulation, yet it is so much more "robust". The people at Roxul are very helpful and are great at technical support as well.

As far as the noise insulation goes, the insulation is 3" and in a 3.5" space (typical 2x4 construction) you leave the air gap on the noisy side of the wall. Supposedly the larger the air gap (within reason) the better the sound transmission loss (less noise).

I am currently looking at 2x6 plates and 2x4 studs installed 16 inch on center on either side of 2x6. It is an economic form of building "two separate walls in one".

Speaking with one of my framing contractor friends, he mentioned that further isolation can be done by simply cutting slots into your 2x4s. This is done by using a table saw (or hand circular saw if you're good enough) to cut a slot that extends from about 6 inches from the end, leaving a 6-12 inch solid section in the middle and continue the cut to about 6 inches from the other end. I would imagine that the cut should be about 1/4" wide which is where a table saw would be easier. I think most blades cut at a 1/8" width. 1-1/4" drywall screws would then be used to fastent he drywall to the studs. This will ensure the screws will not penetrate past the slot and increase the areas of conduction. In this method, you can also get away with one layer of 5/8" drywall insteaad of two. Of two layers of drywall will drastically reduce the STC but it gets more expensive.

As you can tell this is for new construction and is very time consuming versus simply installing resilient channel. In addition it will likely not give as much isolation as RC. However, the real bonus is that it is no cost except for your time.

I would compare this method of construction to a product that is currently out: http://www.quietzoneframing.com/ However, I have priced this engineered wood product and while giving exceptional performance it is expensive. If I had the money, I'd have gone with this product but, alas, I have better places to spend my money (like paying off other debt ).

Bottom line, the better your room is built, the better the sound quality.

My friend's experience is that cutting the 2x4s works. I can not quote any data as to the STCs but it is definitely worth the trouble if you have a very strict budget. I know I am going to be doing this in my new Media Room.