Hi Joe,
Thanks for considering our products and I happy to assist you!
You do have a somewhat large room but since your listening area is confined to a 14 x 14 space, the CBM-170s would be perfect. In such a large room and since bass wavelengths are much longer than midrange wavelengths, I do recommend a high output powered sub. Knowing the SVS models like I do, I think you are in good shape :)
Regarding power, it is in my opinion that because of marketing, power ratings have become a little absurd. The CBM-170 is about 90dB efficient in an average sized room at 1 meter at 1 watt. At as little as 50 watts of good clean power, the CBM-170 will produce 107dB at 1 meter. Or about 100dB at 2 meters. That is very loud.
At 25 watts, you are still over 100dB at 1 meter, and, still over 100dB at 2 meters if 2-channels are driven.
I would honestly say that 50 watts for the fronts and 25 watts for the rears (using your Nad) is perfect. Remember, you will also be using a self powered subwoofer which takes much of strain off of your receiver, provided you set the speakers to small, which is recommended.
Take care!
Good Sound To You!
David Fabrikant
www.ascendacoustics.com
