Isolaion for already framed space.

[LiveWire]

I guess this is going to be the first of a few questions...

But the space is already framed and there is another unit next door. Luckily there are 2 stair cases that kind of separate them. What are your sugesstions for the MOST isolation so my cleint won't annoy the neighbors.

Both floor and wall isolation solutions are helpful. Just remeber we are dealing with already built walls, so acoustical products will be our saving grace.

Thanks Ahead of Time
Dave

[sharward]

Have you been to the Construction Forum here, and specifically seen this introduction, and the important reference area linked from it?

[LiveWire]

yeah i have. I guess what I understand is from Nightfly...over stuff a wall with the "fluffy stuff" example using 6.5" insulation with a good R rating for a 2x4 wall. Is this true. My main concern is isolation.

What materials will make this work the best.

Right now our idea is the fluffy stuff or a 703 in the wall then covered with a metal lined drywall.

If there is anything else you would recomend I would love to know.

[Dan Fitzpatrick]

from what i understand you are wasting money to use 703 inside a wall. hi density insulation makes almost no difference for the lower frequencies. the lower frequencies are the ones that are hard to stop.

also rather than use metal lined drywall you might use multiple layers of much cheaper drywall instead, and also save money.

[LiveWire]

Dan,

At the time i read your post, I think i am turned away from using 703 in the walls.

Would you recomend Roxul or something like "fluffy stuff" and over stuff the walls.

I NEED the best isolation I can get.

[knightfly]

According to a report by Stanley Roller of USG, their findings show that optimum PCF for in-wall insulation for ALL frequencies is 2.5 PCF: this is why pretty much ALL the "SAFB" products (Sound Attenuating Fire Batt) are produced in this density.

However, the way it works is that lighter PCF helps low end, heavier helps high end. Total difference, as long as you actually HAVE insulation in the wall, is only about 2 dB from what I've found so far; but with today's subwoofer culture, and for live drums, etc, it makes more sense to go LIGHTER in weight for improved LOW end isolation.

In actual practice, standard household fiberglass (NOT FOAM BOARD) insulation performs as well as anything (in walls that is) and is lots cheaper than ANY of the higher density material.

Overstuffing the cavities can be done, but NOT TOO MUCH or you will REDUCE isolation by increased coupling of the two sides - I would NOT put 6" batts in a standard 2x4 wall, if I said that anywhere I would have assumed that at the very LEAST there was RC involved, which increases the air space by about 1/2" - RSIC clips and channel increase the air gap on a 2x4 stud wall by more than that, and so slightly compressed 6" standard batts work fine for that.

The purpose of "overstuffing" is to increase the damping factor on the wall panels - if you have LOTS of money, there is now a much better way to go.

http://www.audioalloy.com/welcome.html

One of their tech directors posts a LOT on studiotips.com, join and browse for more info. Also check their other pages at the above link for examples of damping on various materials.

You still need insulation inside tho - GG isn't a replacement for that, just an excellent addition if you're really looking for MAXIMUM isolation... Steve

(Adding GG between layers will add approx. $1 per square foot of wall)

[serge instrumental]

Hi Knightly!

you said: " but with today's subwoofer culture, and for live drums, etc, it makes more sense to go LIGHTER in weight for improved LOW end isolation. "

I'm just confused about it. I understand your next exposé about too much density inside the walls, but "light damping" isn't a good low freq. absorber.

I know that for the surfaces (drywall) need to be dense to attenuate low frequencies.

Again I understand that if you fill your wall with too much dense material, il wil eventually connect both sides of the wall.

But so, there is an in-bettween "density" optimisation?

Xcuse for my english