What to use instead of Corning 703???

http://www.knaufinsulation.us/pdf/BlackAcoustical.pdf

http://www.knaufinsulation.us/products/building_insulation/commercial_building_insulation/black_acoustical_board_ecose.aspx

 Fibrex 1280


Roxul Safe N Sound


Roxul RXL40 


Johns Manville 814


http://www.bobgolds.com/AbsorptionCoefficients.htm

Rock wool and I purchased it from that same vendor. Works amazing

I used OC703.  I got it from a local company.  They had to order it, so it took a week to come in, but it was not any more expensive than rockwool.  the extra costs you might get if you can't find it locally, tho.  it's very big and bulky so it costs more than other things which weigh the same (it doesn't weight much) because of the size.

Owens Corning 703 is just a brand name and product number of a mineral wool product.

Mineral Wool Wiki

From: http://www.ehow.com/about...rglass-insulation.html

"Early HistoryThe first finely woven glass fibers, called mineral wool, were produced in 1870 by an inventor named John Player. At the 1893 World's Fair, spectators were able to view an elaborate dress made from fiberglass cloth. It wasn't until 1938 however, that the first fiberglass insulation was produced. It was invented by the Owens Corning Company, which is the world's number one producer of fiberglass to this day."


Use what ever you wish... any brand of similar density mineral wool that you can source will be more similar than different.


best regards,
mike

If "denser is better", why not just stack up some concrete building blocks?

(Not arguing against the premise, just trying to provoke thought.)

bitflipper


If "denser is better", why not just stack up some concrete building blocks?

(Not arguing against the premise, just trying to provoke thought.)

The densest form of rockwool is called a window pane, but common sense would tell me that there's a happy medium nearer the denser end of not very dense at all.  IOW dense enough.

Get the slide rules and calculators out, fellas, here it comes, it's fart skinning hour again...

Exactly.

Building materials are accredited also for acoustic isolation properties and acoustic treatment.

The fart skinning has doubtless been done to ISO standards already.

Just choose accordingly.   The ISO standard material will bring piece of mind at the extra cost incurred for the material to have gained the accredited standard in order that an architect can specify it by name and be sure it does what it is supposed to, isolate or treat reflections.

Or choose the nearest generic materials having the properties you want, then have doubts and wonder about it ad infinitum if you wish.  You may also choose breeze blocks even if you like but they likely wouldn't have the desired effect now would they?  Just guessing there tho.

The best way to keep a boring debate open is to recommend a generic material and then bring up the idea that variances to that may cause favourable differences or not.

It's enough to make me want to hire a specialist rather than get the best deal...

The 703 now sounds like for a few pennies more you'd at least get some peace of mind.

Perhaps what he was alluding to is that a "single-density material" is going to have optimal effectiveness for a specific range of frequencies, with its effectiveness dropping rapidly outside that range. 

You can actually hear the effect when you employ too much absorption. The room starts to sound muffled and unpleasant, while low-frequency issues remain mostly unaffected. That's how most people end up with too much absorption in the first place: they keep adding more in an attempt to trap low frequencies that are outside the absorber's range of effectiveness.

Ultimately where this takes you is a room response that's actually less flat than what you started with. It would make sense, then, to use different weights and thicknesses around the room to avoid that effect.

There is also a benefit to using multiple layers of lower-density material, so that you end up with the same mass but greater volume. The thicker the material, the more likely you are going to catch a given frequency at its maximum excursion, where the most energy is absorbed.

probably roxul, we covered that one already

matt,

That does make sense.

Only problem I am having now is where to buy this stuff in the quantity I need. Seems like the places that can order it need to have a minimum that is way too much for my needs (as in 5 pallets worth).

Any suggestions on that?

Northeast Atlanta