Thansk to Michael8it I obtained a replacement MW6600 driver to replace the one frozen in my new to me pair of RTA-11's. Wow!!! Playing them with my Adcom CTP-500II using my Sansui 890DB as Amp for now. I like the contour the Adcom has for low level listening. Uses the later HArvard curve which does not increase treble like Fletcher-Munson.
Have only had about an hour to listen. Very open and airy sounding. Nice bass though not as powerful as my AR 3a's. Upper end is not contest.
These are the rarer non-towers. I plan to do a full recap and I'd like to veneer the cabs - that vinyl is butt ugly.
Will also look into Dynamat treatment Mike suggested.