Sub users...

I have been reading about the JL Audio Fathom F113 and one concern I have is that a couple reviews stated that the F113 lacks a high-pass filter, which can be an issue for two-channel use, unless I use an external x-over, which I do not desire to do.

You can always use the sub to fill in and run the mains full range.

Shardone, I have read this elsewhere too, can you explain more?

If I used an external x-over I would cut some of the speakers lower end and control the output of the sub? Without the x-over, the speakers perform as normal and I control the upper limit of the sub, and "fill-in" the bottom? I guess I always imagined the speakers running full range and the sub filling in the bottom.

Sorry, I am a sub newbie! I hope I follow. Can you expalin possible negative effects of running the mains full range?

Lastly, if I were to go the external x-over route, does one have to spend a lot of money to get a good x-over?

I very much like what I read about the F113's, specifically using two of them, and desire to go this route. That said, while I want to do it right, cost is a factor.

i have found that the only way i can get seamless integration with my sub (for 2 chan) is to center it between the l/r. this is most noticeable in situations like you describe, drums that move across the soundstage. this is also thiels recommendation for placement if it is primarily 2 chan listening, 1 sub.
i rarely use it for 2 chan as i think the bass is adequate without.

you can try the subs with your speakers running full range and fill in the botoom ie 35-60 hz and down or get an external xover which I use and get increase in dynamics etc from your mains --2 schools of thought on this with lots of opinions either way --you just have to try and decide which way you like it---rich--glad the little one is dancing :)

Can you expalin possible negative effects of running the mains full range?

Possible problems are matching the large LF phase swings in your mains (due to the double ported design) and/or too much bass at some frequencies.

FWIW: I use the sub to fill-in because I want to take advantage of the different room placement of the sub to allow it to reduce suckouts at the listening position due to inevitable room rear wall reflections and room modes from a symmetric placement of the full range mains. I think this is the best approach if you have good full range speakers and a sub that matches (the drivers and overdamped tuning in my sub precisely match the mains - differing by only a few hertz at resonance). The only reason to restrict full range speakers with a crossover would be in the case of small satellite speakers with 6 inch woofers that can't really handle the LF.

A sub can easily be EQ'd with a Paremetric Equalizer (or TACT or PARC) so that it "fills-in" leaving a pure unfiltered signal to go to your mains. Some subs come with great auto-EQ features. For other less sophisticated subs you can look up Room EQ Wizard for suggestions.

The essential thing is to get a sub that integrates with your speakers! If your speaker resonates and has a highish group delay then a sub that is overdamped and does not resonate will be a waste of money (huge expense for poor SPL output that is tighter than the bass from your mains and therefore a largely inaudible benefit)

According to this article, [url=http://www.stereophile.com/floorloudspeakers/920/index6.html]the WATT/Puppy 7 offers enigmatic measured performance[/url]. This is why it might be safest to get a Wilson sub that is designed to go with them. This speaker is not designed to easily integrate with a sub, IMHO.