What is Floyd Toole saying about extra amplifier power and headroom?

diamonddupree , before you spend $3000 on an active crossover to experiment with sub integration, buy a $149 Schiit Loki Mini tone control. It’s a relatively cheap way to experiment with reducing the driver load on your Magico Mini II speakers. You may find that you just need to roll off the lowest frequencies using the Loki and raise the roll off frequency on your JL Audio sub. You did mention that the Magico Mini’s have great bass extension (for stand-mounts) but if it’s at the expense of the rest of the music the point is somewhat moot.

The attenuation of the bass frequenciy range provided by the Loki may not be an ideal match for your speaker/sub pairing in your room but it will at least give you an idea of how the two interact. You might find that having the Fathom 110 provide more of the range of bass frequencies is a good thing. And may help in deciding on whether or not to purchase an expensive crossover unit like the CR-1..
For reference, I have stand-mount speakers similar to mapman and use two 10" sealed powered subwoofers in a 12’x20’ room. The subs are located at two different positions relative to the speakers. I have the Loki Mini tone control in-line between my preamp and a class D amp using one set of pre-outs and the subs are connected to the second set of pre-outs. I ended up rolling off the bass frequencies to the speakers by about 7dB and actually raising the roll off frequency on the subs to 90-100 Hz. Here’s a graph of the Loki’s tone control frequecies: https://i.imgur.com/XGDm140.png.
Just a suggestion for an inexpensive way to experiment with your setup, not necessarily a final solution.
Tom

@tketcham that looks great. This is definitely the way. I was also just looking at a MiniDSP unit. Is that the same as the Loki? It looks like an active crossover that controls roll off frequencies for anything connected to it. It's also super inexpensive. Thanks! 

@gregm I'm going to look at hi passing the Minis with an active crossover, perhaps the Loki that @tketcham is recommending or a Mini DSP. Both look like inexpensive ways to figure out what's happening. And to answer your question, yes, this is only at very high listening levels. My neighbors love me. 

@onhwy61 I'll try an app to test SPL. Wasn't aware of one so thanks! 

OP,

Although I've heard Magico speakers they were not your model.  Much good advice above (save for one comment on headroom).

I really think that you're trying to drive that 7" too hard.  And due to the slopes of the crossover there is not a "brick wall" at 37hz and 38hz.

I have a tri-amped system using an electronic cross-over spec'd for my system as in cross-over points and slopes.

You need to take the low bass load off the amp, which will take it off the speaker as well.  I think you might try a cross-over at 100hz give or take.
Go here and check out all the possiblilties:
www.marchandelec.com/electronic-crossovers.html
Phil Marchand can be a big help.
BTW, I have the XM-44 (It is tunable with different circuit cards).

Regards,
barts

Perhaps what @mapman was saying about increasing current flow could help this situation. I'll have to look into it. Thanks for your thoughts!

The thing is, when you have thermal compression there is a tendency to turn up the volume/throw more power at it (if there is increased current then there is increased power) but that does not help if there is thermal compression - in fact it makes it worse. But if you are planning to get some of the bass energy off of the woofer, then it will have less thermal compression. So Erik's suggestion should be looked into, as well as a Distributed Bass Array, since the shape of the room really isn't relevant (I'd talk to Duke at Audiokinesis about that since he is really one of the few selling a DBA-dedicated sub system).