Cornwall iv

Interesting on the room correction, not sure what to think there and why it would be different than other speakers. You might get less room reflections with the horns. They tend to be a lot more narrow and need less room treatment/correction in my experience.  
 

Does room correction need to be engaged to run a highpass? Even if you chose to highpass at 40hz I would imagine the transition will be clearer. 
 

I normally highpass my JBL 4367 (similar layout to the Cornwall) at 63hz but one of my subs is broken again (JL is trash). So I am running just one sub at 37hz to fill in the bottom end at the moment. Even at 37hz the highpass made a big improvement in integration than just using a a low pass (I tried both ways), food for thought. 

@james633 ,

I think you are on to something with the high pass. I haven’t ran room perfect again yet but set my crossover at 60hz both the subs and the speakers. Sounds better for sure and more dynamic. Gonna enjoy it that way till tomorrow and re run the room correction and see what that does. Sorry to hear about your JL sub. They will fix anything to do with a V1 Fathom for $450. I sent the amp in and they replaced a bunch of caps with the V2 caps and sent it back within 2 weeks. It sounds better than it ever did now. 
 

The guy I bought them from gave me a room sweep printout and they started falling off the shelf at 55hz a little bit so I think 60 is good. May play with that some more. 

Yes 60hz is probably good. Honestly most speakers start rolling down at 60hz and then they “crossover” with the port. I find speakers sound better if I crossover where the bass driver rolls down before the port is engaged. That has been my experience with a number of speakers.

the big 15” woofers with accordion surrounds are very good in the mid bass because they settle fast and have a ton of surface area but deep bass is not their strong-suit due to low travel.

JL is good about fixing subs ($550 for full rebuild out of warranty) but this is my 5th failure (4 prior rebuilds, 2 per sub) so I am done and moving on to another brand. 

I definitely noticed an uptick in the mid bass speed when I applied the crossover.  Very good improvement indeed. I need to get the wife and kid the hell away from me for a weekend so I can experiment!! lol. Prob not gonna happen anytime soon. Daddy daughter dance with my second grader Saturday night. Haha. 

Wow that sucks about your experience with JL! I had 10 years of trouble free service out of mine. Only had it back for a few months after the recap of the amp. Hoping it’s good to go for a while but yeah with your experience I would be done with them as well.