Whisper Room foam replacement

[siper]

Hi guys,
This should be an easy one. I bought an 8x8x8 Whisper Room from the 90s for $200 that I'm planning on using within my 20x18 garage to play drums. The frame itself is in great shape but the original Auralex foam on the inside is garbage. I'm planning to replace all of the foam with 2" Rockwool and it looks like Rockboard 60 is a good candidate based on the results listed here:
http://www.bobgolds.com/AbsorptionCoefficients.htm

The problem is that I can't find any of it locally and it's pretty expensive to ship. In fact, it's hard to find any Rockwool products locally. Theyd need to special order a pallet of it, but I only need about 300 SQ ft.

1. Will something like Safe N Sound or Owen Corning alternative perform about the same? Or is there really a dramatic difference between them? Any other brands I should looking at that are easier to get? I'm most concerned about low end absorption.

2. I'm planning to cover the rockwool with @ generic canvas or fabric. Does the cover material matter if I'm not looking for additional absorption?

I appreciate any advice you guys can give. Thanks!

[SoWhat]

Greetings siper,

For drums, a Whisper Room will not provide adequate LF isolation. 2" of Rockwool will not help that situation either (you need much more), although it may attenuate your cymbals. How much isolation you need depends of course on how close your neighbors are. Also, ventilation should be a primary consideration. Do you have a way to get fresh air in and out without sacrificing isolation?

All the best,

Paul

[siper]

Thanks, Paul. Will Rockwool help at all or is it just a waste of time? LF attenuation is the goal, but definitely looking for any reduction within the whole spectrum.

But yes, I've got ventilation worked out already.

[SoWhat]

Greetings once again,

As I mentioned in my last, 2" of material will do nothing for LF. And if you don't treat for LF, you've really done nothing for your isolation. Also, you need to remember that drums are around 110-115dB, sometimes higher (115 is safe to plan for). I don't know if the Whisper Rooms provide more than 25-30dB of reduction (my recollection; could be WAY off). You'll need to check on that.

You should read the many threads that wind up being devoted to LF isolation/attenuation on here and other forums. The professional designers and acousticians are of great help, and their input on those threads will answer all of your nagging questions.

All the best,

Paul

[Jag94]

I would start with playing drums in the whisper room, and have someone on the outside take measurements with an SPL meter at various locations in the garage, outside the garage, and around the property. Or better yet, get a drummer friend to play, and YOU walk around with the SPL meter. That is the only way you are going to know exactly how loud it really is, and how much work you need to do to isolate the drums. There is a free app on the iphone called NIOSH Sound Level Meter. You can set it to C or even Z weighted and it will give you very accurate measurements.

Before you do anything, or spend any more money, I'd get those measurements first.