[basementjack]

Fred, what are the dimensions of the room?

if you are 'trapping a freqency' in your room, that is if exactly half of a 50hz sine wave fits into your room, then no amount of EQ can truely fix the problem (though i supposed you could notch out 50hz from your setup, which would not fix the problem, but would eliminate the source (kind of like cutting off your leg because you have a sore foot - when a padded shoe is really the best answer to let the foot do it's job))

You'll find that a reasonable size (2-4") panel will do well so long as you give it some space between the panel and the wall. A popular technique is to put one diagonally over corners.

ok now here are a few thoughts...
If you have a Radioshack sound meter, and a laptop (or a PC near your theater) - there is free software you can use to measure the response of your room. if you are capable of this, it should be the foundation of anything you do, and you should use it to validate that what you are doing is working.


Its been suggested that a compressed roll of homeowners insulation has decent absorbing properties.
Yes it is ugly. but it is also cheap. if you really want to 'hear' what the difference is in your room with some absorption, 2-6 rolls of insulation would do the trick - once you hear the results, you can decide the best way to treat the room permanently (very likely via commercial panels like GIK or realtraps). if you've used the software and measured before and after, the difference will not only be audible, but it will be documented too, and then you can post back the results here.