Separate Amp for AV receiver

 I agree, separates are the way, I guess when I purchased this about five years ago I was hoping it would perform as well as my old Yamaha A1. Not even close. I'll start looking into a new AV system. What do you think about Emotiva?

I use a completely different system for my music, all McIntosh separates with Bowers & Wilkins, sounds fantastic. Can't say the same for my theater system and I would like to bring it to an acceptable quality, maybe I'll keep the Denon for a minute and change out the speakers first.

Alright, I've decided upgrade the speakers for my HT first, they are twenty+/-. I started with a new subwoofer. Just installed a new REL 7X. I also have a REL S/3 SHO for my two channel system, along with my 803 D3s, so I would like to go with both subs by connecting my Denon AVR4300 direct with the REL 7X, and using the "Longbow" REL wireless connection to the S/3 SHO. I can't seem to get them to pair although I've tried multiple times.
Anyhow the sound is much improved with the new 7X. My front speakers for my HT are NHT 2.5i, very efficient speaker. The rears are ceiling mounted Klipsch, don't know the mod. #, but they have three speakers facing down, front and rear. The upper clg. mtd. fronts are Boston Acoustics with front facing and rear facing speakers. The Center channel is Martin Logan Motion 50XT.
I think I'll keep the center channel, it's only a couple of years old, but change out the upper rears, and upper fronts first. 
Please advise, what do you think.
Thank you

That could be the issue, I'm keeping the Martin Logan though, what do you think about SVS?

I would consider the little MLs, the ESLX. I have seven Mains and surrounds, 2 subs, but only one working for now. I may mess around with it tomorrow.

Sealed off, dedicated room, 22'X22', my stereo system is perpendicular to the HT system.