10dB resonant peak at 40Hz

At that frequency, a high pass filter at 50 hz might work.

I just set up a sub with a high pass on my mains. It's an astounding and wonderful difference. Just having the low end coming from the floor instead of 30 inches above eliminated most of my 60hz resonance. 

The difference in clarity with the mains freed from low end duty is pretty dramatic. Coupled with clean and even low end it's even better than I expected. 

After playing with the parametric eq, I ended up not using it. Playing with the low pass roll off curve was more helpful in blending the low end.. And variable phase surprisingly making a big difference. Still fine tuning but much closer than ever to "the sound". 

@atmasphere 

My single sub with the HP filter is doing such a nice job, I'm considering adding a second. But I'm concerned that while two may fill the room more evenly, I'm inviting phase issues with two sources. I'm thinking that one reason a single sub sounds so good is the absence of two sources of low end interacting with each other and the room. 

I've already found that adjusting the phase on my SVS SB1000 Pro has a significant effect on the overall balance but with two it could get much more complicated. 

Your thoughts?  

Your concern about hearing resonance rather than music can be addressed by a combination of HP filter and sub. By reducing the energy below 60hz in your mains and REPLACING it with a sub with DSP that you can move around, you would have some control over the low end. The SVS subs have great DSP software that can tailor the FR precisely in the low end without affecting the overall SQ of your mains.