@david_ten
I’ve payed attention. For one, I disagree with the presumption that "treatments from GIK are quite cheap". I have personally been in communication with GIK. Price/value ratio is always a personal matter and opinion, with respect to what is cheap, or not.
I do agree, however, that "even natural rugs or wall hangings will be better than synthetic foam". In my case, this is somewhat moot. I realize there are materials "better" than foam. No matter what is obtained, there is always something "better", especially in this hobby of audio and the quest for utopia/nirvana.
I’m satisfied that the foam I’ve installed has done the job I intended, which was merely to "take the edge off" so to speak. No doubt though there is more to be had should I choose to go that route. I appreciate the/your tip.
EDIT:
So here’s my analogy.... I’ve used foam not with the intention of scoring a home run, but merely to get on base. And to that end, I’ve certainly achieved it. This despite with Geoff would lead one to believe which is that it does nothing at all..... or further, that it has a negative effect. WRONG. I have plenty of third-party independent lab results, my own ears, and testimonials from other users of acoustic foam to reiterate that acoustic foam is a solution, albeit not necessarily the best solution.