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

Hello,
Typically an amp will increase wattage when driving lower ohm loads. A 100w amp might go to 160w at half the ohms.  It doesn’t always double, but it usually increases. I don’t think power is an issue unless you hear clipping at higher levels. The rock wool could be a little too much if It is really thick. You are drowning out the mids and highs. And the drapery could be too little. Especially if it is not symmetrical. Room treatment is an art. You could be absorbing too much of the highs and those treatments you talked about do very little for bass. Plus the left side should match the right. You might want to switch or add defusers so you don’t kill your highs. At low levels your 7” drivers are balanced or barely keeping up. When you turn up the volume they could be drowning out your mids and highs. I think you need to test with near field listening. If your speaker wires are short get some cheep longer higher gauge wire and put those speakers in a 6’ - 7’ triangle to you. Remove some of the sound of the room. If it sounds really good it’s not your amp or the speakers. It’s the room. Redo the room treatment. Last but not least. Get two subs. My speakers are rated to 25hz. I still have two REL 9t subs. MC has four in his room and he has monster Tekton Moabs. Subs balance out a system and make it seam like your system is a 1000 times bigger even at the lowest volumes. Like I said your 7” drivers might not be moving much at low volumes but a sub can. When you rock out the sub can take over every thing below 50-80 hz. To do: Near field listening to determine is your equipment matched, balance absorption by removing or less thick rock wool to balance curtains, diffusers instead of absorption in some areas. (GIK.com), last but definitely not least a sub or two (sealed and 10” driver/s) stay away from ported subs- too sloppy in most cases. 

The combination sounds excellent to my ears at low to moderate listening levels, but I notice a slight compression in the soundstage at higher levels.

That's what the OP originally wrote.  I understand that to mean the soundstage dimensions shrink at high volumes.  Is that an accurate understanding?  If you have a smart cell phone, download an SPL meter app and take a measurement of the volume level you start to hear this "slight compression in the soundstage".

As mentioned above, the compression you hear is more likely to come from the 7 drivers rather than the amp. The obvious way to find out is by trying a higher spec’d amp on your speakers -- if the compression is gone, go for a more powerful amp.
That should be your first stop.If it’s the drivers, you need to hi-pass the signal going to the magicos, either at ¬60 -¬80H (half or a whole octave above the speakers’ -6dB point). In other words, limit the amount of bass the magicos have to produce thereby reducing the strain on the woofers, and channel those frequencies to your sub.
Any active Xover can do the job, including the one you mentioned.


But it’s strange the drivers overload so fast -- you must be listening very loud :)

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!