From Four 12 inch Woofers To Eight 12 inch Woofers, Will I Get Deeper Bass Or More Bass?

68pete, according to all the posts I’ve read here on the ’Gon regarding integrating subs into full range speakers seamlessly, it sounds damn near impossible. 

This is for 2-channel listening only...this is not a home theater application.

In a real sense, more bass and deeper bass are the same thing.

Bass rolls off for any given distortion spec and any given roll-off (deviation) at a given frequency. So...

If you want bass at -3db to a 90db reference level at X% THD, your current setup will roll off at (purely illustrative example) 35hz.

Because you have added more surface area to your woofer array, the woofer excursions will now be shorter at 35hz. Because THD increases with excursion, you have effectively cleaned up your bass at -3db at 35hz. It’s now less than X%.

You’ll now find that, for the same X% THD at -3db from your reference, you can crank the system an extra 3db. X% THD Bass will now be available at (say) 30hz -3db. You may have to adjust your main speakers at the x-over point to maintain flat response, but you will get “deeper bass” from the new set up, all else being held constant.

Well, then, mitch4t
it appears that you are all set...

If you follow the methods for integrating a subwoofer suggested by "The Sound Doctor," you should have no problem with a sub in your system. Here's the link ... http://www.soundoctor.com/whitepapers/subs.htm