Optimized Center Channel

You have a very common issue once you expand from 5.1. Also think Marantz HT receivers make this worse. You can always raise the gain on the center channel, but that can lead to it being out of balance, when panning dialog will change the volume. 

Almost all HT receivers have "dynamic range" adjustment. Find the setting and play with it. What it does is change the DB difference between the lowest sound and the highest sound. All multi-ch movies are set to be played at "reference volume" at this volume the dialog will be crisp and clear, but it will also be shaking the walls when any action happens. To compensate for this, you adjust the dynamic range. You will get the dialog volume boost, it will balance the lowest low and highest high out. Mine is set to low most of the time, have no dialog issues at all. 

Also when doing room correction, you can select the volume to adjust to. Reference volume is default. That will set it all up to be played at a loud volume. Reference on a Marantz receiver is "0DB" My volume is usually in the 30's when watching a movie. 

@sunshdw Yes, I agree the cost of the UMIK is $79.  If you go through the "put it in your cart and pay" process, there is the tariff and shipping to deal with.  Been there, done that a few times with the changing tariffs.  Amazon et al sell it for $139, which is the same cost as buying directly, except you save shipping time from Hong Kong.

@mm1tt77 Yes I am versed in KScape, it's a fantastic product. You would correct that in the cases of a stream only movie or TV show so, no, the KScape wouldn't work. 

KScape isn't an app based product like an AppleTV. Meaning you don't loads apps onto it in order to access content, they are direct to the content. Here's a link to their store if you want to look around at what movies and tv stuff they have.

https://www.kaleidescape.com/movie-store/

You can rent or buy whatever they have so functionally it works like Apple+ or Prime or whatever else. 

There's a lot to it and I could go on and on but I'll spare the boredom :-) 

@soix 

I’d still try disabling the center speaker and trying a phantom center, because if that sounds clearer/better it might indicate a problem with the center speaker. 

Absolutely agree.  If you have a good pair of main speakers (ones with a big 'sweet' spot, a centre speaker only contributes to comb filtering, especially if it is designed like a D'Appolito array on its side (most are)!

Marantz AV gear during its Audessey set up phase will detect the lack of centre speaker and add the centre signal to front left and front right.

Oh, at least in Australia, video streaming services have woeful sound quality in general.  If anyone thinks 4K when streamed is the same as 4K from a silver disk ... just look at the bit rates

Last night during my evening HT session, armed with the information graciously offered here, I listened with a more critical ear.  Overall, I have to admit the center speaker's output is very good.  Dialog is clear and generally intelligible. Enough so that I could turn off the subtitles?  No. 

Then why fix what isn't broken?  I spend an awful lot of time and money tinkering, tweaking and upgrading to improve sound, so why not try to improve upon the middling dialog we are so often served?

Reflecting on the day to day, I long for the ability to add subtitles to normal conversations (I wish there was a remote to mute some conversations, but that's a whole other story) and therein, methinks, lies the problem: aging ears.  My hearing is good enough, and a recent audiology test showed I am not yet a candidate for hearing aids.  However, I do find myself missing bits of conversation because someone's head is turned away from me while speaking, they don't speak loud enough, or ambient/ background noise interferes.  Thus, it appears the problem is me, not the system.

I sat on the floor for a time yesterday to have the center speaker pointing directly at me, and it helped somewhat.  Moving between the couch and the floor, the difference was very subtle, but it indicates speaker position could be improved.  With the addition of a new amp and change in the placement of one of the subwoofers, I have to run Audyssey again.  That will be a good time to experiment with the phantom center.  I also fiddled with the EQ and bumped up the enhanced dialog mode one notch, from medium to high, on Marantz.  @mswale , my volume is typically around 40 when watching.  Depending on the source, I might have to increase it to 35, but not much more (unless no one else is home).

Considering my recent purchases, getting a new center speaker is out of the question, particularly as mine works well enough.  A more logical investment is a new AV rack to provide more flexibility for equipment placement, particularly for the center channel.  And, in a few months when Black Friday rolls around, Dirac.  The Kscape is an interesting concept but I'm not ready to go that route.  Had I not recently acquired the Apple TV-X, I might have viewed it differently.

Robert