1MoreFord

You already know your room setup is not the ideal situation you see posted everywhere. It may be difficult to get an educated recommendation. You may want to find a dealer(s) who has a liberal cheap/free return policy and buy the 600m ii's and the 502's. Try both and return the losers.

I've found B&H normally the best for new with KEH the best for used equipment. It's their mainline business. I'd put Robert's Camera Used Photo Pro https://usedphotopro.com/ right after KEH with Adorama and B&H behind them for used. There's also MPB camera https://www.mpb.com/en-us but I haven't used them enough to rank them yet. I buy used with complete confidence from KEH or Roberts but make sure I read the Adorama and B&H ads and terms Very carefully.

I was looking for the basic specs for the JBL subwoofers to give you a starting point for reference. I found the page I linked to thru a basic search for "JBL PSW-1200 owners manual". There were several hits to choose from and I chose that one since it referenced the specs prominently. More searching may turn up better info for your purposes.

Here are the basic specs for your JBL sub. https://www.hifiengine.com/manual_library/jbl/psw1200.shtml Looking thru the Amazon info you'll be hard pressed to find this info but if you do you'll find many/most of the Klipsch won't meet them. I second the previous suggestion. Expand your search.

Back in the ole days there were "loudness" buttons/switches on systems. They were meant to do exactly what I think you want. They would attenuate the lows(especially) and highs of the music so we would appreciate it more at low volumes. You could try cranking up the bass and treble knobs while listening at low volumes.

Don't forget to budget for any possibly needed additional computer horsepower and the equipment bearers.

Little Rock

I've got 'em nearby too.🤣 https://littlerock.craigslist.org/ele/d/little-rock-klipsch-lascala-al5-speakers/7729839452.html

I'm somewhat new to this, for the second time, myself but my take and suggestion would be that your AVR is good enough(and better than mine!) for your speakers. I'd say upgrade your center channel to at least the Rp-450c or Rp-504c. Look at Amazon for authorized vendors, currently good pricing, and the ability to return painlessly if you don't like one of them. The next thing I'd look at is your Sub since your sub specs only go down to 29hz +/- 3db and Low Frequency Effects in movies go 10-15hz below that. Sorry no recommendations for a sub.

Link doesn't work here either

No longer posted.

With those constraints I'd go for the rp-440c since the freq response goes lower and the sensitivity is higher but make sure the size of the 440c speaker works for you since it's larger than the 404c. I like that it's cheaper too. I'd also caution you to make sure whichever you buy it comes from an authorized Klipsch dealer for the warranty. https://www.klipsch.com/dealers

I keep missing or forgetting about those out of country availability/shipping problems.😳

Ooops, I did that too quickly last night. I saw the 2 pack as 2 singles.😳 If you run red to red or black to black it will work. Better yet, here's 15' single. https://www.bestbuy.com/site/best-buy-essentials-15-subwoofer-cable-black/6458775.p?skuId=6458775

If you mean the **450**C speaker instead of the 440c I'd go for the RP-450C because you can get them from Amazon for $280 OR the RP-504C for $369 with EZ returns if you don't like them.