Summary:
Even at the showroom, on a barely competetant Sony-ES receiver, I could tell that the detail on these were stunning. Stevie Ray Vaughn's "Chitlin's Con Carne" had deep punchy bass and cymbols that just hung in the air. The resolution is so nice that you can hear the snare wires in the snare drum. Not individually, but snare hits are not just a "plop" sound but rather have this texture that is very lifelike.

I took these home to my Carver electronics and was not satisfied. I jumped into a pair of Cary SLM-100 tube monoblock amps and hit a very special combo. These speakers are fast enough that poorer quality solid state amps really display their odd-order harmonics, and the resultant sound is bright, rough, and irritating, especially on many of the compressed digital drival that mainstream music has been churning out. That "metallic" sound many complain of (see the '90s reviews) is the sound of cheap transistors, people, unappologetically displayed in all their inferiority by the Ren 80s. People with mainstream solid state need to look for slow cone speakers that just blob-over the edges that cheap transistors crap out. But if you get very nice solid states, or into tubes, which inherantly don't produce odd-order harmonics but rather the lovely juicy even-order kind you are in for a treat. Violins, horns, guitars, pianos, cellos, drums, female vocals, oh man, I can't really list all the instruments that really shine. The details such as the musicians breathing, sheet music being turned, saliva, environmental noise, aren't exactly attractive examples of the Ren 80s details, but point to the degree of resolution these exhibit which provides a stunningly realistic portrayal of the music, which is obviously what we're all after.

These are very power-thirsty, though, so single ended tube amps sound very lovely but can't get much volume. Go for a high power push-pull tube amp if you can, or an extremely smooth solid state (tough to find). I upgraded my cables to very large, low capacitive ones and upgraded my CD player with an output section that could outpower many little receivers, and the bass is about one more tweak away from no longer needing my SSW-212 sub (only used for sub-40Hz anyway). For my previous listening room which was very large, I added a pair of rear-firing EMITs (like the Epsilons) for nice effect. Unless your rear wall is more than 4 feet away, don't do this though.

I also refinished these in a nice cherry color, and removed the grill cloth and refinished the grill cover so the drivers could be displayed in their beauty.

I have to say that even after 5 years, there really isn't a speaker system I would trade these for, except the $14k Epsilons. Not counting the rest of the electronics costs, I have to say that for what the speakers are able to achieve for their price is an impressive value. Keith Herron from Herron Audio has listened to this system and was pleased. It did take a lot of effort to improve the electronics to the Ren 80s standards, but I've never found these speakers anything less than very enjoyable as a result.

Strengths:
Amazing detail, texture, especailly in the mids. Very impressive bass depth for an 8" driver.

Weaknesses:
Most electronics are too rough for the resolution of these planar magnetics.

Summary:
My experience with the Renaissance 80s has been basically a good one, although there have been some negatives. This speaker, of course, has been discontinued, and Infinity seems to have lost interest in marketing mid-sized (i.e., afordable) planar speakers.Previously, I owned a pair of Infinity Modulus satellites with a Velodyne 15" sub and was very happy with the setup. But the Moduluses were clearly too puny for the living room in my new house (20' x 30', with a 16' ceiling), and so I became intrigued with the Rennaisance 80s. This seemed to be the logical "step-up" model to the Modulus. No dealer in my area, however, had a pair in their showroom to audition.
Finally, I took the plunge. I ordered a pair from a friend who works for a sister company to Infinity; he was able to get them at dealer cost. I took them home, set them up, and decided after 15 minutes that I hated them! Even after several days and much repositioning and tweaking, that opinion didn't change. The problem seemed to be in the EMIT tweeter, which was of a different configuration from the EMIT in the Modulus. It "beamed" at you, making everything sound raw and edgy. Strange, because this is the same driver as in the top-of-the-line Epsilon.
Rather than take them back (a political decision here), I decided to keep the speakers and modify them. First, I substituted the EMITs out of my old Moduluses (the planar membrane is narrow and tall, something like a mini-ribbon driver). They retrofitted perfectly on the front panel. Next, I re-did the crossovers, using premiun parts such as Solen caps and 14 ga hook-up wire (the latter was very tough to work with).
The result was a much smoother, better-integrated speaker than before. With my Velodyne ULD-18 II, I can achieve fairly hefty concert hall levels in my living room, with reasonable transparency and soundstage realism. Recently, another tweak (reversing the polarity of the woofers) tamed an unruly resonance in the crossover area around 500 Hz. I think the woofer enclosures could probably be redesigned for smoother response and lower resonance. I'd give these speakers a 4 out of a possible 5. Only certain electrostatics such as the Martin-Logan ReQuest outscore the Renaissance 80s. This or the CLS might be my next speaker, or possibly one of the larger David Lucas kits. Has anybody out there had any experience with these?
The rest of my system consists of top-of-the-line Rotel, with a SME 3009 Series II tonearm, Shure V15 VMR and handmade turntable (based on the AR design, but with such amenities as an outboard, variable-speed power supply), and custom low-capacitance cables.