Acoustic Material for control window

Hi!! I've got a very large window directly to my left in our control room. It is causing some nasty high frequency flutter from the opposing wall. The room isn't particularly large either. I was wondering if this http://www.ebay.co.uk/itm/160657406078? ... 1423.l2649 car 'acoustic material' would be do the job in reducing the early reflections from the window? Marc

Hi Marc. Please read the forum rules for posting (click here). You seem to be missing a couple of things! :) Regarding your question: No, that stuff won't do anything to kill first reflections. It is way too thin, and doesn't have the open-cell structure that is needed. The best solution is to buy a panel of Owens Corning OC-703, 4" thick, cut it in half (vertically), and put one half on each of the side walls, at the first reflection points. If you can't find OC-703, then ordinary mineral wool or fiberglass insulation will do. The most important thing is that it mus be thick: 4" at least. You can make it more effective by spacing it away from the wall as well. For example, leave a gap of 2 or 3 inches behind it. - Stuart -