Bose Smart Ultra Soundbar - subwoofer upgrade

[Pete Shields]

I've just changed my system from a Denon 3400 amp and 25 year old Bose acoustimass 15 5.1 system to a Bose smart ultra soundbar. I've had it a couple of weeks now and am getting used to it. I'm going to give it a couple more weeks to get used to the change in sound, but it does seem a little lightyweight in the bottom end. Does anybody have one and have they added the 700 (or 500) subs to their systems and would they recommend