Need Help on TDC Speakers


I have in my possession two main speakers. They are quite large each speaker has two 10" woofers, two 4 1/2" mids, and two tweeters. The only label on them shows them to be manufactured in Massachusets and it states "TDC-20". In the research I've done I discovered they may be proto-type speakers from the late 70's or early 80's and they may have some link to the Tannoy company. Please help me identify and possible assign a value to them. Thank You.
rsposa
TDC was a Tech Hi-Fi house brand manufactured by AAL in Chicago. AAL eventually became MTX.
I owned a pair of TDC speakers during the early 70s while in high school. They were purchased at Tech Hifi to replace my home made speakers. My father bought them for me after we listened to JBL, Advent, BIC and probably a few others. The TDC were made exclusively for Tech Hifi and were an inexpensive alterative to the previously mentioned brands. I enjoyed the heck out of them back then. Don't remember what happened to mine and wouldn't expect them to be worth a lot of $.
I still have a set and love them dearly. They are 350 watts a piece and had 2 10" subs, 2 6" mids, and 2 horns. I too purchased them from Tech-HiFi in the 80's.