Room acoustics

And for those of you with decent French there is a wealth of information here: http://www.homecinema-fr.com/forum/acoustique/

All right y'all, I've posted some interesting waterfall plots on my systems page.  Check them out.  There are three measurements:
: The first is my room without any extra bass treatment, other than the bass panels behind my speakers and the acoustic panel stuck in the corner.  You can see the bass is a mess and there is a nasty frequency around 120 that lasts forever.  That would be the one-note bass i've started noticing.
: The second is with a big, potted orange tree in the corner behind and to the left of my left speaker.  There is a three panel glass sliding door on the left wall. You can see the bass is much cleaner, the bass that didn't want to die is now dead and the whole graph is much cleaner.
: The third is with a quick limp membrane bass trap I whipped up last night.  I used some dynamat i had from a car install to cover the top of a 5 gallon bucket, with a blanket thrown in to stop it all rattling on the tile floor. As you can see, it's not as clean as the orange tree, but the one note bass isn't there either.  The midrange region is definitely a bit dirtier than with the orange tree, but it's better overall than having no extra bass treatment. 

The orange tree is, oddly, the best sound treatment for my current issues. Ha! The problem is that it is sitting outside right now so it gets more sunlight so the oranges can ripen and in the summer it's outside all the time.  This means I'll need something that can either be a permanent part of the room or that i can move in when i move the tree out.  I thought I was just dealing with bass decay problems, but it looks like that corner gets a lot of midrange reverb, probably from the large amount of glass right there.  Curtains aren't an option. We have a clean look and blinds would make it feel cluttered and small, a problem in a basement with 7 foot suspended ceilings..

Thanks very much. This is interesting. You can clearly see that things get dirtier below the Schroeder frequency, even with your orange tree (wish I could have them in our climate). If and when you use a computer as a source, you could use it to equalize the low frequency response. If you like that, you could get a miniDSP to do the same with other sources.
I also like the clean decor, but yes hard surfaces like glass windows also make for a dirtier response. No equalization will help you there, only soft surfaces etc. There are some minimalist looking slotted panels etc that apparently dampen mid and high frequencies (often used in modern meeting rooms).

What I find particularly interesting are all the frequencies below 20 Hz.. I start my sweep at 20, so where is everything what coming from?

*where is everything there...