Center Channel Dialogue

Your center is an excellent center speaker and I don’t think chaning speakers will improve vocals. I had an ML center and it was excellent. But the MLs aren’t very sensitive so you need to make sure the levels are adjusted.

Have you set up the levels on all your speakers using the setup in your AV reciever? My guess is your center level isn’t set right. I don't know how to set up your amp but I have a denon AV amp and the manual setup mode it goes from speaker to speaker playing white noise and I adjust each level until they are all the same volume. In your case you might want the center channel up just a little.

Jerry

@carlsbad2 

Yes, I did adjust the center level on the Marantz pre-pro to max. I also adjusted the equalizer to add more volume. It doesn't seem like a volume level issue now, more of a comprehension issue. Cupping my hands seems to direct the sound waves from the center speaker to my ears, if that makes sense. 

@soix 

Thanks for the SVS suggestion. I have one of their subs and really like it. I'll look into their center speakers also.

OP,

First of all, I am really sorry to hear the problem you are having. Second, there is something very wrong. We have had a great home theater system and a bedroom system (currently a 65” with a Sennheiser Ambeo sound bar) for at least 30 years and never experienced anything like you are. Dialog (typically 85+% on center channel) has always been really easy to understand, never difficult to understand in the least. Your speakers are good and unless completely defective cannot be the problem.

The problem has to be something very big… nothing little like your center channel angle.

When you go through the surround equalization procedure tne center is at the same volume to you as all the other speakers?

The only thing that comes to my mind is your surround processor has a faulty center channel.

@hillbilly559  I agree with @ghdprentice  here. There is something very wrong here. You don't have to do any of these extra stuff to balance left, center, and right speakers. Marantz should have three options for the center channel: phantom, normal, and full range. I would first use phantom option. This will allow the left and right speakers reproduce the center channel. Use the built-in test tone generator and see if you get same sound from left-center(phantom)-right channels. I suspect your receiver may not be decoding the center channel at correct level. If that step works, then take the center per-out and connect it to a separate amp and connect your center speaker to that. If that works, then your Marantz amp driving the center channel is the culprit.

I have use Yamaha receivers in 7 speakers + 2 subwoofer arrangement and never had this problem. There is something fundamentally wrong here.

Have you tried eliminating the center channel all together and allowing the processor to ghost it back in?  I know my home theater setup is anything but idea, but I run a 4.1 setup and certainly have never had any issues with understanding dialogue (at least nothing that subtitles wouldn't resolve...LOL).

I know that a center channel should be superior to not having one, but it might be worth at least seeing how the sound changes.  It might help diagnose the issue.