Best Way to Integrate Subwoofers?


What’s the best way to integrate subwoofers with monitors, or speakers?

I’m not referring to placement, or room treatments. I’m referring to what’s the best way to integrate via a crossover, without a custom dedicated crossover.

Do you run two separate signals to the subs vs the speakers and supress the lower frequencies to the speakers, while supressing the upper frequencies to the subs? It would seem that this method might allow you to move the crossover to higher frequencies, relying more on the subs for the bass and lower mids - if that is beneficial. It would also seem that this method would permit you to taylor the slope of the crossover to minimize overlap of frequencies between the subs and the speakers, which might improve clarity - depending on the capability of the particular crossover used. And, I suppose it implies / requires a separate crossover to be used to run both signals through to route the mids and highs only to the speakers and the bass and lows only to the subs.

Or do you run the same signal to the subs and speakers and just emphasize the subs up to the bottom of the frequency range of the speakers, crossing over from the subs to the speakers at that point (crossover notch). It would seem that this method would require you to fix the crossover at the bottom of the frequency range of the speakers, wherever that may be, and would not require a separate crossover to be inserted into the signal path. And it would seem to imply that the slope of the crossover would be limited to the slope inherent in the subs and speakers, which would limit the flexibility of the crossover.

Or, does it make any difference?
bassdude
I also use the JL Audio CR1 and am a big fan of it. I run dual f112v2s and crossover right about 50Hz.  Barry Oder also helped me integrate my subs using the CR1.  He is fanatical about it. Unfortunately, I have heard he has recently left JL.
Anyway, James makes good points about the benefits of running deep bass through a crossover, in that it reduces the workload on your main stereo amp, and also decreases the vibrations in your speakers.  The downside, however, is that you are adding another component into the chain and also need another pair of interconnects (additional cost).  Overall I’m happy with it though.
The Cr-1 is such a great unit and it does not add any character of its own in my opinion . It’s transparent.
barry now has his own consulting business and does house calls. I had the great pleasure of having him over for 2 days in my house .
when u call Jl Audio they still talk about what Barry bought to the industry lol, even after he has left. 
With my pair of f-113 v2 and blades2 the crossover I have set at 90hz . 
In my opinion and decade of working with subs I totally agree with James. 

I'm confused.

My Primaluna HP has a sub out RCA tap that I run to a B&W sub. 

Would I be better off using a Subwoofer Crossover?
One of the main reasons I like high level inputs and letting the sub do it's own low frequency filtering is that you keep the signal as pure as possible for the mains. I think this is especially important if you listen to an analog source...you definitely don't want something in your chain doing an ADA conversion if you've gone to all the trouble of investing in a high end turntable/phono preamp. I think if you can't do high level inputs to the subs (speaker wire from your amp) since a lot of subs don't offer this feature, the next best would be using an rca out from the preamp to the sub while still running the mains full range. Set up the sub to only fill in the low end the mains can't do. This will take some time to get right... although a lot of people will go the dsp route to handle splitting the signal, this will definitely be be easier to get right, but can't look past the ADA conversion... that bugs me.
Thanks newtoncr for your post. I could never understand why audiophiles are so against crossovers. Your link to http://www.soundoctor.com/whitepapers/subs.htm is greatly appreciated. I found it very informative and reaffirming.