Welcome to the Forum, Terriss!
Your receiver should have enough power to get you started just fine, and it has a good DAC in it. As for being hesitant about getting floorstanding speakers for behind the sofa, keep in mind that stand mounted speakers have the same size footprints as floorstanding speakers, but without their sensitivity and bass capabilities.
As for me, I have a pair of La Scalas (on 13” platforms) on either side of me, and a Heresy III directly behind me, for a 6.1 system. This is in an 18 x 19-foot room, and the TV is still 11 feet away, with lots of free space in front of it. It can be done!
While it’s tempting to try to buy the ultimate system right away, you don’t yet know all you will after a year on the Forum, and upgrading is half the fun. I started out with a pair of used 32-year-old La Scalas and a used $150 receiver, and the system has grown as I have learned. You can see it listed just below, and it now contains things I’d never heard of at first, like the Electro-Voice Dx38 speaker processor/active electronic crossover.
Get your system and while you’re enjoying it and hopefully learning from and participating in the Forum, you’ll see if you’ve arrived at a system that’s ultimate for you, or whether you’ll start wondering about bigger speakers, and everything that goes with them. Tip: most of the Pro Theater speakers are only 24” deep, and will fit through normal home doorways. <wink>
As for your question about getting an external power amplifier, there are many varieties. Do you want Class AB, Class D, 2-channel, 7-channel, 11-channel? I didn’t get one for the first two years, then I got one. Then I learned about bi-amping, and I bought a second one, along with lots of money for the things it was needed for. Not so simple, right? As I said in the first sentence, your receiver is just fine. It’s the top-of-the-line Yamaha receiver, and is far above what most people start out with. You could be happy with it for years. Happy listening!
A very general description from my experience:
Paper In Oil: Very warm, good detail. Possibly the best sounding. (Russian PIO's good value good sound, Mundorf & Jupiter considered the best)
Film and Foil: Best bang for the buck. Also warm, maybe a bit brighter than PIO. These measure very well, some of the lowest ESR ratings. Can almost match detail quality of PIO's. (Solen SA, SB, SE, SM, SN, SY Series, and Mundorf ZN represent great sound and great value. I've never really heard a bad sounding F&F)
Metalized Film: Cheapest to buy but may be only minimal improvement over cheap polys or electrolytics: If you get good ones sound improvements can be described as SMOOTH. (Mundorf good but expensive, Clarity Cap sound great and better value)
Oh well, those LaScalas were extremely ugly and I got them for next to nothing. It was a regular pair (non industrial) that had been cut in two by the previous owner to become some "split industrial" - because he was using them as PA speakers. There were metal handles that would vibrate at high level, and two holes on each side of the tweeters with some cheap piezo tweeters that you could toggle ON with some switch. Woofers were not original (I should have kept those somewhere, they were of the Tesla brand and were GORGEOUS). But finding LaScala for cheap in Europe is already a miracle.
Every unused part has been separately sold including the crossovers.
Right now using Peavey FH1 bass horns and still using the K33 but I want to replace them with Kappa 15C because I use subs and I'd rather have a bit more midrange definition.
Posted April 4, 2020
I'm looking for a good pair of older Klipschorns--preferably around the
late 1970's model. Would be willing to drive a ways to get them. I live in
Roseville/Sacramento, CA. If anyone knows of a pair for sale, please tell me. And if you have
any particular suggestions about which ones to buy, I welcome them as well. I currently
have a pair of 1977 Cornwalls and would like to add the KHorns.
I can be reached directly at firstname.lastname@example.org
Thanks a bunch!