Thanks for the input Steuspeed and Mdhoover. I should have mentioned that back in my two channel set-up, I had a B & W ASW 675 placed inside the armoire. There were no problems with extraneous noises. However, If I placed one sub here it would be very close to the sub on the outside of the armoire. Far from being an expert, I would expect that this could not be such a good thing in sonic terms.
I believe that you are both right, and I will probably just go with one sub.
I believe that you are both right, and I will probably just go with one sub.