Center and Mains

Many AVRs have the ability to direct extra unused channels to the front L/R speakers for bi-amping. I do this with my Yamaha to ease the load on the amp.

You have a 7 channel amp, try bi-amping your mains and see if it helps.  Personally, I think you will see the most improvement in clarity by matching your front three speakers.  I'm not knocking mac or def tech, they all sound better by matching all 3 fronts.
Don't bi-amp mixing the Denon and Mac.  I would try using the Mac just to power your front 3 speakers.

Sure, nice! I'm already Bi-wired - Thanks I'll check it out. 

Sorry to say I cannot give you an answer because I have not heard any of your particular pieces of equipment, although they all seem very nice. I am however familiar with Mcintosh amps. I can only relate to my experience with my own equipment. I think that I was able to "clean up / reveal those little hidden jewels within a recording / sound track" each time I moved up the lines with different speakers first and then tried different amps to see how they affected the speakers. Also, it would probably help more to match all three front speakers and then work on the amplification. Hope this helps!

Mike

IMHO, the biggest problem is the extremely bad match between the center and main speakers. Having different brands absolutely ruins any chance of timbre match and then there is a 6db sensitivity difference between the Def-Techs and the McIntosh.

Sounds in the front may come from a single speaker, or they may be created with L&C or C&R speakers, and that is a problem with the mismatch.

Read this article, especially the last line.

http://www.avtruths.com/speaker.html

Sounds in the front may come from a single speaker, or they may be created with L&C or C&R speakers, and that is a problem with the mismatch.

So the sensitivity would create a path of least resistance and push gain left or right? If I can’t change the speakers to match, can I amp up one or another to offset the effect? Maybe Bi or Tri-amp my center?
Having owned many Def-Tech speakers already, I really tried to go that way with my new center, but their centers available were not a match for the older 7000sc’s and considering the demand I was wanting ask of the center, it just wan’st going to cut it. I like the sound I have, even if it is sort of "hodgepodge".
I was watching "The Rewrite" last night and felt just "folded in" amongst a few of the tracks. I’m wanting to tweak / balance / squeeze my existing speaker system.
Side Surrounds: http://www.definitivetech.com/products/mythos-eight
Rear and Back Surrounds: http://www.definitivetech.com/products/sr-8080bp

If you can't match LCR speakers you might set the menu of your processor to center speaker = none so the processor will generate a phantom center image.  I think that is better than a timbre mismatch.

You can change the speakers to match. Here is the matching center for your L&R that is recommended by Def-Tech,

http://www.definitivetech.com/products/cs-8080hd

An amplifier will do nothing to overcome the timbre mismatch.

In a 2 channel system, the speakers create a balanced image with sounds that come from anywhere in between the 2 speakers and even outside the speakers. Now if the 2 speakers were different, that image would be totally ruined.

In a multi-channel system, that perfect front image can be created with 3 identical speakers, however that is only possible in certain situations. The next best option is to use the timbre matched center that was designed by the company to go with the L&R. If seating is tightly centered between the L&R, the "phantom center" that was mentioned can work well in some cases. Any other center speakers will just degrade the front sound, and IMHO, trying anything with amps, processors, etc is a waste of time. Doing this will always make it sound different, but never right, and your ears know that. When it's right, your ears won't tell you to "clean up" the sound.

Lol thank you. Good points. I had auditioned the 8080HD and frankly (it could have been me), but it didn't even come close to making the grade. To me it sounded "thin and without body". I wish that wasn't the case, it would have saved me about $6K. Nevertheless my investment has been made so I'll look forward to Bi / Tri-Amp testing!
Thanks so much guys for offering up your experience and ideas.

Mac's are not known for having great speakers.  You really should consider a new center.  USAM has multiple pairs of Def Tech speakers listed that will match the sound of yours.  You don't even need a powered sub in the center so something like a 450 might work for not much money.  Buy a pair and only use 1. Or, if you want to go crazy, there is a pair of 7004's listed...

Otherwise I totally agree with comments above about going "phantom" for the center.

My question is can I add power and find those nuggets or should I
forget the power and find the right processor?

The processor it is. MX122, Marantz 8802A?? 

You have received a lot of great suggestions, almost all of which was to try and match all your front speakers first but it sounds like you want to get a new processor any way. So, let me make this suggestion. Buy a used processor first, maybe an MX121 or an 8802, see if they make the change you are looking for. If not, since it's already depreciated, you can resell it and not take too much of a hit and answer you own question as to whether a different processor will do what you are looking for. I think you will take the greatest "hit" on trying to re-sell a brand new processor as far as equipment goes. They just seem to drop like rocks pretty fast. Just my $.02, good luck either way!

Jsigle,  
Michaela says it best.  If you tell us what city you are in, maybe another member can stop by with a nice pre/pro and let you play?
The other option is to buy on-line from a retailer with a money back guarantee.  Emotiva & Outlaw do that.  Even better, skip the pre and try an Oppo.

I'm in N Alabama. I have a Marantz dealer close and have reached out for a demo. Your point about used is a good one and that's one of the reasons I've moved to separates from an AVR. Making it easier to keep up with tech. What is a Oppo?

Oppo is a DVD player that plays almost every format on disc.  It has a nice built in volume control, great quality, nice DAC and tons of features.  Go to oppodigital.com

Thanks I'll read up on them. Lots of accolades I see.