Separate Crossover for JL f112 Subwoofer?

Is the separate Crossover really necessary for JL f112
Subwoofer or I can just run the cables from Preamp and
use the JL onboard crossover. Thanks
I don't think it's necessary. I'm use an F113 with a pair of Avalon Indras, and they blend really well together. Not getting any annoying overlap. Very pleased with the result.
Sound like you talked with the JL tech guy. I've called JL tech service twice and both times I've been switched to Barry Ober. He is an independent audio shop owner He promotes the use of outboard crossovers and happens to sell them. He doesn't have much to say in support of the use of JL's excellent onboard crossover although he doesn't dismiss them either. Very odd arrangement JL has IMHO.
Yes. I spoke to tech guy but I cannot to recall the name.
It could be the same guy. I was told the same thing.
My speakers goes down to 40Hz so it shouldn't be a problem
to use JL's onboard crossover. I also spoke to the guy's from
Store that sell's JL's and they hooked up Jeff Rowland Capri
to JL f112. For main speakers they used Sonics bookshelf
speakers. Sound was great and when I asked them about external
crossover, they just said NO.
i'm running the F112 with on-board x-over set at 80 and my mains (era d14's - solid down to the high 30's) on "Large" blend is good with no issues. electronics are pioneer SC07. I have tried both sc07 xover as well as the JL and did not notice any differences. I'd suggest trying the onboard and if you find that lacking see if you can borrow or sample a external unit before you buy. I've also run the JL crossed over higher (>120) and it still sounded great. someplace it should have issues but I don't know where.
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Adding a sub affords the opportunity to use digital room correction in the bass. Units are available from Audyssey, SVS (using Audyssey technology), and Velodyne (my choice). Cross at 100hz or so, and you can clean up most of the destructive room effects. For me, this is the primary benefit of a subwoofer. Just MHO. You might also need/want an external active high pass unit like the Marchand or NHT X-2.