Go for sub or larger speakers?

Martykl, I'm sure in some systems your approach will work better than running the mains at full range. Its a trade of between smoother integration and the degradation of running the mains signal through an additional active filter. If I had gone down this path, I would personally not have used the NHTX2, but get a higher grade crossover like a Marchand XM44.

This may be pure snobbery because I have no proof whatsoever an XM44 sounds better than the cheap NHT, but I would not like the idea of running my main signal through a cheap crossover when I have some very high grade electronics upstream and downstream. (Sort of the "weakest link" theory). Your appear to be owning some fairly expensive kit yourself, so I would definitely try out a higher grade crossover sometime and see if you get any improvement.

Hi Sashav,
Alot of opinions here. My experience says, if you like the sound of your smaller speakers and your amp will power them properly for the room your are in, you are fine and can achieve wonderful results with a subwoofer. You can run into a problem crossing. If you do not us an electronic crossover to cross your satellite speakers where you want them to blend with your subwoofer, you will need to cross your sub woofer around the 3 to 6db downpoint of your satellites I use a subwoofer now and cross it @ 40hz (its lowest setting). My speakers are 3db down at 38, I set the woofer low and slowly added until it was smooth, played a bit with the phase switch, had to move the woofer a couple of times, but ended up with a very smooth transistion.
As far as woofer size... on a properly designed woofer, size does not matter. A designer should have more motor to match the mass. Good 15's are fast, but you should try to listen to the sub that you want first and consider your room size, an 8, even a 10 would not move enough air for my room.
On the other hand, if you really like the larger speakers.... your done.

To sub, or not to sub? I'm with the "depends on the room" contingent. In some rooms you just cant get "fullrange" speakers to work (without correction).

One more thing you might want to consider: if your main speakers are ported, you may want to plug the ports. In my experience, if your mains go relatively low it can sometimes help integration with the sub. On smaller speakers I usually leave them open. Lots of variables to play with, all rooms and set-ups differ.

Edorr,

I've definitely thought about the x-over issue. I borrowed a (used) Marchand from a local dealer for comparison and it worked well, but it was noisy, which was more intrusive than the NHT. Of course, who knows whether that was just due to the condition of that one used example.

The main reason I haven't pursued it is that I can't decide whether to go for a high end HT pre/pro solution or a higher "pedigree" stand alone x-over. I'm kind of embarassed to admit that my power up regime -1)preamp, 2)SMS-1, 3) NHT, 4) DAC, 5) power amp has me thinking that a pre-pro (Theta?) replacing #s 1 thru 4 might be nice. Not sure I'm ready to punt and go that way, but I'm not sure that I'm not ready, either.

But, your point is definitely taken.

Marty