Hello all,
nice place you've got here!
I liked the Advent, too, even if it almost upstaged me when I hauled my first serious speaker design into the local high end shop for a demo. The much anticipated Avents had arrived just an hour before.
A speaker demo that left a lasting impression on me was a reel to reel playing through a pair of the big Phase Linear amps (700s?) each powering an AR LST (12" woofer, 4X2 or 3" dome mids and 4X1" dome tweets). A drum set demo was playing and it was easily the closest approach to the sound of the real thing I had heard up to that point. I'm not sure I've heard much better since. I think the key was enough driver voice coil in the mids not to get into thermal compression and enough power on hand to have a little headroom.
Remember the Speakerlab ribbon driver? I seem to remember learning that Bob Carver had some connection with the Speakerlab folks and his "Amazing" speaker used, essentially, the Speakerlab ribbon for the mid-highs.
To answer Pacifico's qustion, I think in general things in speakerland are getting very much better, especially at the two frequency extremes. Tweeters of the 70s tended to be nasty little things with serious peaks in the wrong places.
Bass in most speakers of the 70s was very wrong in many ways. I thought Advent was one of the better ones at the time, but those couldn't begin to approach the better contemporary designs, like my SP Tech Timepieces which, in concert with a pair of good subs for 15-30Hz, produce some of the very highest quality bass I have ever heard.
I love good bass, I have listened critically (and hopefully) to a lot of speakers over the years and almost always found the bass seriously lacking in quality, even if everything else is pretty well right. This includes my own designs, with one exception. In the last 35 years I would say I have heard what I would consider to be great bass fewer than 10 times, maybe 5, and two of those times was in my own system, and even there I don't take full credit - there was a lot of luck involved.
My point is, though, that bass in general from more recent speakers is of a much higher quality than in the 70s, thanks probably to good box design programs.
I think we are entering into a golden age of home playback, especially as regards speakers and to a lesser extent, amplifiers.
Look at the variety of fundamentally different designs on the market at this moment. I can't think of any time in the past where we had so much choice.