I have a pair of Original Large Advent speakers. They are Franken-vents.
Bought them used ca.1973-4 from the original owner who had sold them and then bought them back. I think I paid about $100.
The second owner was an EE student who replaced the original crossovers with his own design.
Sometime around 1976-7, I smoked one of the tweeters during a loud party using a crappy amp driven way beyond clipping. (I think that was the time the cops showed up, but I may be, uh, hazy on that detail. I mainly remember the Mrs. and me not getting arrested despite the cloud of, uh, smoke that rolled out the front door onto the cops. I will forever be grateful to them for just laughing and telling us to turn it down and leaving.)
So the repair guy replaced both tweeters with factory "fried egg" replacements (so they'd be matched and all.) When I picked them up, the repair guy asked where we got those crossovers? Nice design, he said.
We used them for many more years until the woofer foam rotted. We got some Klipsch Quartets to replace them, which I still have. (They've since been refurb'd, too).
The broken Advents sat in at least three garages for 25(?) years as we moved about.
A couple of years ago we were setting up a bonus room in our new house. I wanted a stereo in there, but didn't want to spend a lot of money. I sent the Advent woofers off to some guy in Nashville to have them professionally re-foamed. I resurrected a 15 year old honest 100w Denon AVR from a closet to drive them. I made some speaker stands from $5 wooden storage crates from Lowes, painted black. I replaced the grill cloth (that we'd previously replaced with something darker) with some fabric that looked more like the original. I still had one of the original badges in a sock drawer, but had lost the other one. I found some guy on e-bay who makes exact replica vintage speaker badges, and he provided perfect matches for just a few dollars.
Anyway, I was just listening to them today. Loud. They sound great. I came downstairs and told the Mrs. "With the music selections and the speakers, it sounds like 1970 up there! Except with a better amp."
Yeah, they're by no means perfect, but that's not the point of these speakers for me. Good times, good memories. Much fun.