Klipsch RP450C Center Channel - would like some input

[EJC]

I recently replaced the ML SLM wall mount Center Channel speaker with a Klipsch RP450C in my system.
The change was a major improvement in the sound field of the system.
I reset the speakers manually and did not use the Yamaha YPAO.

I set the receiver crossovers to those specified in the speaker manuals and then adjusted the volume levels using an SPL App on my phone.
 

The results were a significant improvement over the previous setup. 
I have been happy with the results.

BUT, I've noticed on some (not all) surround sound videos (streaming) the voices, specifically, the male voices will sound "grainy" or sort of like old turntable rumble. Sorry, hard to describe but so far that's the best I can come up with.
The issue does not happen with all videos
1- I guess it is possible that the problem is more related to the recording then the system.
2- The 450C is a ported, could the port be part of this issue?
3- The 450C is placed 9" from the wall.

I currently have a rag stuffed in the port to see if blocking the port will make a difference. So far the sound is still good but I'm not sure yet if it is affecting the problem.

Has anyone closed off the port on the 450C?
Has anyone lined the interior of the cabinet with Dynamat?
Any other ideas?
 

[wuzzzer]

It's the recording.  100%.  I've experienced exactly what you're describing also.  Klipsch speakers will not mask poor recordings like other speakers do.

 

Don't stuff any ports.  9 inches from the rear wall should work great.

[EJC]

8 hours ago, wuzzzer said:

It's the recording.  100%.  I've experienced exactly what you're describing also.  Klipsch speakers will not mask poor recordings like other speakers do.

 

Don't stuff any ports.  9 inches from the rear wall should work great.

Thanks, it's reassuring to know someone else has experienced this issue.
As I get older (66), I also have to question my hearing being an issue.

[xo705cf]

I couldn't agree more with wuzzer....

I have 280fs and a rp-250c, and quite frankly some material sounds like crap to me the sound almost sounds like it's washed out and I don't know how to describe it... however when it's a good source the sound is incredible no mistake about it....