I know this is heresy, but...

Warnerwh, I do understand where you are coming from.. It is amazing how much we will spend on gear, gear, and More gear! But gets tuff to justify 500 or 1000.00 on room treatments. Well I myself was not capable of doing much before recent due to finally getting a room I could do somewhat a dedicated area. And today I am getting a bunch of fancy Lenrd Corner traps from auralex with cubes etc.. for the corners in my room cause now I am driven to see what happens with more control over the room. However, I don't think this is limited to having to put dedicated acoustic designed material in a room.

I found with my surround system I could add a 200 pound very full and puffy couch really works with very similar effects. We did this with my friends room as well in his 2 channel, and if you pull the speakers out of that room they fall flat, but with his giant full room couch surrounding them they have so much impact you would swear there are massage chairs built in everywhere. So if your in a very steril Ikea furnished room, yes you will have lots of issues more than likely, and people with these huge investments that really think their 20 k speakers are performing well would be shocked when they get to hear them in a room that is not just a wood floor with a glass end table and that metal framed 1" cushon audiophile chair. I would go as far to say that in general many showrooms you go listen to this stuff in is very similar and why it always sounds bad, with a 1/4" thick commercial carpet, end table and some 500 dollar chair that looks good but is nothing for sound absorbtion. I notice this issue at all these pictures of the shows in hotels too, basically Card table chairs sitting in front of bare wall, hard metal components, and a pair of stellar speakers that just don't have a chance in such an environment.

Note that many of the best sounding rooms seem to utilize something in the way of portable acoustics, or even several Plants placed throughout the room, now its all I notice in many of these pics is the PLANTS! nobody notices this, but they serve purpose, Add humidity to the room, have some diffusion, and the pots with heavy dirt etc.. can have some bass trapping properties.

Undertow and Warnerwh,

How much acoustic panel treatments did you need to add before you noticed an improvement in the bass? Square footage or linear feet of bass trap? What do you recommend if you desperately want to minimize the amount of ugly panels covering walls. What is most effective in a corner...a Mondo trap from Realtraps?

Shadorne,
actually I have a similar trap to the realtraps, its from Gik, and it works pretty well when you span the corner as a hemholtz type should.. Cleaner response, way better Vocals in my experience, its weird but it cleaned up the lower midrange a lot too..
Beyond that I found that the panels minimum will be very dependent on the room size, actually a smaller room does take more due to so much reflection vs. a bigger space that kinda helps itself much more, not to say this is exact and that a big room can't benifit from many treatments as well.
Anyway I say Definatley killing the first point reflections on all sides of a speaker, via floor, ceiling, and both sides really helps. And some bass trapping in corners can resolve and increase response quite a bit too. Getting rid of any echo is key I noticed as well, but all this is relative to listening position, how much furniture, and what kinda space you have I would guess.. I am not an expert at all, just now realize the common sense benifits of even some simple treatments.. Diffusion etc.. is a whole other thing, and basically keeping things pretty well balanced seems to be the key.. Also, I kinda notice if a room looks like it will not sound that great or feels it, then it will not sound that great. Some care in setup can go a long way I guess, but I have limited experience in only about 4 different areas that I have somehow got to sound pretty dam consistent vs. when first just sounding like crap.

Shadorne, by the way I just saw your setup, and being everything is like flush mounted, and other issues being inside the walls etc.. with a pretty good sized area, and very Hard walls built around everything, you would be almost forced to maybe try something with return policy or get the professionals at Rives audio draw you up something very effective.. I could say this you have a very non traditional type install for the guys running 2 speakers out in the middle of the floor looking for 3 dimensional sound, I know enclosing my speaker cabinets into another cabinet within a wall would restrict a ton of air and space.. So you may be best just going after the most Bass trapping possible with aesthetic appeal you can in that room and hope for results with your subs. Or add a lot of large couches! But seriously you have a very different and other set of issues the traditional crowd probably does not deal with.

So you may be best just going after the most Bass trapping possible with aesthetic appeal you can in that room and hope for results with your subs

My thoughts exactly. Big rooms are generally better than smaller rooms but they can suffer from very long reverb times in the bass (end to end). Currently a PEQ has all the room modes well under control but my thinking is that it might be better (more natural sounding) to do more with bass traps on the rear wall to dampen long reverb (about 10 feet behind the listening position). I am struggling whether it will really do much to improve the extreme LF?

FYI: I am generally very skeptical of tweaks but following advice on a Genelec website lead me to be pleasantly surprised. The other thing that convinced me was Doug Sax Studio. Doug won a life long achievement award from AES for his work on audiophile recordings (Sheffield labs etc.) and he built this studio in 2004 with soffit mounted speakers in a half wall.