Not tamed but improved!
So a lot of bass traps does do something below 100Hz but certainly does not solve the issues, in particular the big dip around 50Hz (I tried everything to solve this - moving speakers and chair, checking everything including the equaliser was working properly, and searching for peaks all around the room. I've still no idea what causes it but surprisingly adding 10dB with an equaliser was able to fill it in - to hell with the rules!).
Of course not only is the frequency response improved - much smoother, but the delay times have radically changed for the better. Indeed this is probably the biggest achievement of the room treatment (the ringing at 40Hz is mostly external traffic noise. It's clearer on a spectogram).
Looks good! But you still have about 25 dB of frequency response variation in the low end. Here's what mine looks like using the REW's waterfall display:
I have some room build up in the very low end and no matter how many bass traps I throw at it, won't be much help... But as you can see, a very flat frequency response.
I wonder what it does to the overall balance of the reverb time in the room. Since you have REW, you can switch to the RT60 display and show the balance between 100Hz to 10 kHz on the horizontal scale. Here is what mine looks like when I was reviewing the D&D 8c's:
My room is still quite lively with about 400ms of Topt (REW's measure optimised for small room acoustics as technically there is not RT60 in small rooms). I am at the top of the reccomended range for my size room which is between 200ms and 400ms. To get a similar display, use REW's overlay feature and select RT60 and it will calculate Topt for you automatically and then change the horizontal scales to 100 Hz to 10 kHz.
Like I say, I have nothing against passive acoustic treatment, I have just enough in my room to balance out the RT60 (or Topt) to be flat in my room, as you can see above, but not too dead sounding. According to Toole and JJ's research, we hear the direct sound more than the sound after it. i.e. our ability to hear through the room. If you have an opportunity to try some room correction, I think you will like what you hear. Would give you the best of both worlds, provided the room isn't overly damped at higher frequencies (hence checking the RT60/Topt above 100 Hz).
Cheers!