I have a mixer (Yamaha) that I connect to my Denon 3312 using an adapter (1/4" plugs to RCA). It works fine for my karaoke
parties (Infinity 2 P362 + 2 Velodyne SC-600 subs).
I would stick to JBL pro speakers + JBL pro subs.
I've tried the big Yamaha pro speakers. I thought they sucked even though there were plenty of "great reviews".
I'm not so sure if Mackie is any better than Yamaha.
So personally I would stick to JBL. You know JBL makes some $60,000 speakers. And they are owned by Harman International who are probably #1 in research. I'm not saying all JBL or Harman speakers (including Revel & Infinity) sound the best. But the odds are in your favor when betting on JBL vs some other brands. Just my opinion.