12-05-11: Stanwal
... I have found it ALWAYS better to run the speakers full range and only use the subs to augment the very bottom end. True, you don't relieve the amp of some work but on the other hand you are not running the signal through another crossover which will invariably degrade the sound. If you like the sound you now have and just wish to augment the bass I suggest that this is the way to go. If you want to play louder with more boom go the other way.
This is predominantly my experience as well. I have done eight different subwoofer installations, and in most cases (especially for music-only) I get the best sound running the mains full range and leaving them out of an additional crossover, while blending in the sub from the bottom up. The only system where I use a high pass crossover to the main speakers is in my home theater setup. In that case, the crossover is to take the strain off the smaller center and surround speakers, but I still run the L-R floorstanders (Mirage M5si's, good to around 26 Hz) full range. And I get the best overall sound and clarity setting the sub crossover to 40 Hz.
For my current 2-channel music-only system I run Mirage OMD-15s full range and use a pair of Mirage MM8's crossed at 50 Hz to augment the low bass only.
Running the mains full range seems counter-intuitive, but even running them that way I still experience more 3-D imaging--the main musical images pop out into 3-D, and the dynamics are subjectively improved. Again, counter-intuitive, but it works for me.
12-17-11: Erictye
Well I just set up the sub for about 20 minutes now. I had a DBX drive rack PA kicking around. I had to run some cheaper lines as my Purist are rca only. ... I need to do a bit of fine tuning yet. I have a question. On my C2300 I have to outputs to go to amps. Can I run the sub amp directly to the second set of outputs thus eliminating the DBX drive rack. What are the pros, cons doing it either way.
How are you using the DBX Drive Rack PA now in relation to your Cremona Ms and the F113 sub? Are you using it for room correction, as a high pass crossover to the Cremonas, or both? If you're using it for high pass, before you try much else, try running the Cremonas full range, and blend in the F113 from the bottom until you notice it, and then back off until it totally blends. It won't cost you anything and it may make wiring for a second sub much easier.