Best Musical Sub

Have you tried setting the crossover high enough to encompass the kick drum and time align the sub to the main woofers? You can do this by ear with trial and error. Clarity is maintained through the midrange without bass bloat. I really don't think you want to pressurize the room, but just have the impact, right?

What frequency/slope are you crossing at? Per Rhljazz, if you want that kick drum fundamental handled by the sub you'll need to cross high enough to route the signal accordingly. Depending on the slope you're using, that may well be north of 100hz. I also agree with Bob's observation re: the room. My own experience is that dealing with all these issues - time alignment, room nodes, crossover point, slope and phase, etc - makes it very difficult to optimize subwoofer set-up by ear.

I'm a digital room correction guy and - even tho Audyssey my get you drummed out of the audiophile club - believe that it dramatically increases the chance of excellent subwoofer integration.

Yes, very good points . First the subs is correctly timed and in phase with the Wilsons. I am live sound engineer / system designer by profession. I use the same measuent system that I use for large PA's in arenas wich is Ration Acoustics Smaart. This software with proper mic and IO will show you phase traces among other things to prrfectly align the two sorces. You can even see the phase shift change as you change the X-Over frequency .
I tried higher x-over points but the JLF110 just doesnt sound good to me in my room at higher ones, currently it is set around 70.
The room most certainly has some issues. It is 14x22x a tall vaulted ceiling. I have a fair amount of room treatments but the tall vault just does what it want to with the bass. Wich is a long decay below 50 and a big dip at 50.
All that being said, the single 10 sub just does t sound right. Now with some recordings the Wilsons on there own are perfect, but with many older ones, they need a little help IMO with the low end .

At that level, stereo subs would work best. TBI Magellan vIII subs/amps are phenomenal and are the most room placement insensitive subs I've ever used. Used them with Avantgarde Duos and they kept up. The other option is a pair of Vandersteen 2Wq. They can be challenging to wire into a system depending on where the amp is located but set up properly they blend perfectly with the main speakers. Having owned WP8, I found the proximity to walls can really impact the mid bass. If you haven't moved them around you should give it a try.