Hi, came across a pair of QEDs, which from the outer appearance, in very good condition. Because the rubber cover cannot be removed cannot tell the under the hood condition but Im assuming good also for its age but prepared for  potential issues. So a few questions, any general thoughts on this 40 year old speaker? Do you recall if the surrounds are foam or rubber, and based on the description what would you consider a very fair and not insulting to the seller price offer? This would be mated to a Yamaha cr 820. Thanks much, Dave
I worked for an audio store that carried DCM back in '78. The Time Windows ($660 pr) sold well. The QED's ($480 pr) weren't as popular - though they were basically 1/2 of a TW. And both sounded similar. Excellent pulse response - coherent sound - 90 db sensitivity. I eventually bought 2 pairs of TW's. And I would have been just as happy with QED's instead! Both models remain as examples of affordable speakers that can compete and challenge big-buck designs - then and now! Thank you Steve Eberbach (DCM)!
The surrounds are rubber and should still be good! Early versions used Philips hexagonal frame 6 inch woofers glued into the baffles. Later custom round frame woofers replaced the Philips. Tweeters remained Philips mylar domes with wave guides (response 15 kc). Ported cabinets - prism-shaped for the TW's and rectangular for the QED's.
I am presently listening to a pair of TW's (52779, 52780). My third pair! RGR 4 preamp and GAS Son of Ampzilla. Speaker wire is Q Audio Time Stream (1980's). A real nice retro system I put together from my collection of vintage gear! 
A fair price for the QED's would be about $250. Your Yamaha CR820 will work just fine, though I encourage you to eventually get a pre/power amp similar to my own setup. DCM speakers do really benefit soundwise from better quality electronics! Enjoy!
@roberjerman,  I remember Ampzilla. I didn't know he had a son
@OP, DCM is one of the speakers I still remember from my early forays into hifi stereos. They and Vandersteen are etched into my mind.
Roberjerman thank you very for your insights, I learned a lot. I will follow up should I be able to pick them up. Gdnrbob glad that I was able to spark a fond memory. Dave
We carried both DCM and Vandersteen in the 80's
I think the TW are OK for sure
brighter than Vandy of that time....but good sound for sure
I still want to see roberjerman's list of gear squirreled away....
Way back in the day, there was a store near Kerrytown (Ann Arbor) closing out a pair of the largest model of the Time Frames.  I was so tempted, but I was poor.  I changed my mind the next day, went back, but they had already been sold.  One of several significant purchasing (or non-purchasing) regrets.
I still have mine ... bought them around 1980 or so.  They sounded very similar to the Time Windows, which were awesome, but beyond my budget at the time.  They have survived the other components I bought back then- integrated amp and tuner (Onkyo T-9 that I wish I still had), and a Philips 212 TT (now a Rega P3).  I still think they sound pretty good.  I think the weak link now is my Sony receiver, which I want to upgrade, but not sure to what.  I suspect the cartridge (AT VM540ML) is not a good match for the phono stage, or maybe the phono stage isn't much to begin with.