New system has fatiguing, harsh high frequency sounds. How to fix?


I just purchased my first audio and home theater system (other than a bluetooth speaker or computer speaker system). I use it for listening to music as well as watching movies. It is a tremendous upgrade and I’m enjoying it. It has clarity and detail that I have never heard before. However, I notice a harshness in the high frequency sounds when listening to music.

I would like my treble to be smooth, sweet, soft, silky and gentle. Right now it is the opposite of that. It is annoying, screechy, metallic and harsh.

I am seeking a solution to that issue. From the little I have been able to find on this subject, it seems that room acoustics might be a big part of my solution. Is that true? If not, what is my next step? An equalizer? I can’t see many options for big changes in speaker placement. At most I can move them a few inches or change the angles.

My listening room is about 11.5 feet by 11.5 feet and square except for the doorway in the back corner which protrudes into the room 18 inches x 44 inches. In the room are a bookcase, couch, end table, media center stand (holding TV, center speaker, receiver, disc player and Roku), computer & computer monitor, my speakers (and rear speaker stands), a ceiling fan and that’s about it... I’m describing the room on the assumption that the room (or its contents) are relevant to the treble problem I’m describing. (However, throwing some thick blankets over my TV and computer monitor, as a test, did not change the issue.)

Here are my home theater components:

  • Computer monitor: WASABI MANGO UHD400 40" 3840X2160
  • TV: LG OLED65C7P 65"
  • Receiver: Sony STRDN1080
  • Disc Player: LG UP875 4K BLU-RAY PLAYER BestBuy SKU 5979504
  • Streaming Box: Roku Ultra streaming player (model 4660)
I mention the monitors (and their size) in case they play a role in reflecting sounds.

Speakers:
  • Front 1: Polk Audio RTi A7 floorstanding speakers
  • Front 2: Polk Audio RTi A5 floorstanding speakers
  • Center Speaker: Klipsch RP-250C Center Channel Speaker
  • Subwoofer 1: Polk Audio PSW125 Subwoofer
  • Subwoofer 2: Klipsch R-112SW Subwoofer 
  • Rear/Surround: Polk Audio RTI A3
Speaker Layout: 5.1 layout with two pair of front speakers and two subwoofers.

The front speakers are on either side of the LG TV on the front wall (and near the room corners. The front speakers are angled in. Minimum distance to wall is 10", but measuring straight/parallel from back of speaker to wall is at least 18". From side of speaker to wall is at least a foot (one side of room has 30 inches). There is only 3" between each RTi A5 and RTi A7 speaker.

The rear speakers are behind the couch at each corner and against the back wall.

One subwoofer is in the back corner. The other is midway on the other wall and angled toward listening area.

For music, I usually prefer listening in 2-channel stereo. The dual pairs of front speakers are awesome. (I initially started out with a 7.1 layout but I prefer this layout now.) The high frequency problem exists even in 2-channel stereo. It also exists if I use only 1 pair of front speakers.

Wiring
All speakers are bi-wired, except the center (and subwoofers), which don’t support it. (Not bi-amp’d, just bi-wired*.)

Speaker wire: Mediabridge 12AWG 4-Conductor Speaker Wire (100 Feet, White) - 99.9% Oxygen Free Copper - ETL Listed & CL2 Rated for In-Wall Use

* https://www.qacoustics.co.uk/blog/2016/06/08/bi-wiring-speakers-exploration-benefits/

Banana Plugs:
  • Mediabridge Banana Plugs - Corrosion-Resistant 24K Gold-Plated Connectors - 12 Pair/24 Banana Plugs (Part# SPC-BP2-12 )
  • Sewell Silverback , 24k Gold Dual Screw Lock Speaker Connector
  • Ocelot Banana Plugs, 24k Gold Plated Connectors, Open Screw Type
BTW, my prior speakers were the Edifier e25 Luna Eclipse. I thought they sounded good and I did not remember them having these harsh high frequency sounds. After listening to my new system for a week, I went back to those for a test and they sounded horrible in comparison. The harsh high frequency sounds are much worse, and every other aspect is worse as well. (That shouldn’t be a surprise given the price ranges being compared, but my incorrect memory had been that they didn’t have this issue.)
lowoverdrive
As for break in, not surprisingly as mechanical devices speakers need a bit of that. Harbeth say a few hours will do, and that was indeed my experience, even if the difference was never more than minor.
Using toe in on most speakers will have very notable changes on upper treble response for wide range of speaker designs, primarily because of greater degree of output fall off at the side is greater in the upper treble range over others. That said, I find that sense of brightness people mention is more often related to mid treble response instead. Add the fact that hearing acuity and energy levels of the recorded music is typically less at the upper range only is compounding. Still, even mid treble response will fall off faster over its range as compared to the bass or mids.

You will impact the sound stage and central imaging as you experiment, so take your time with a new position. Changes like placement time to determine the overall effect. You do get an idea if its close early on, but fine tuning is an effort over time.

Speakers do break in, likely more so than most others in the audio chain. Spiders, roll surrounds, and even certain cone materials will adjust over the initial hours of use. 
Looking at your set up it is clear to me that you are sitting way too close to all those speakers especially given how tall/big they are. No wonder the sound is not too your liking. You need another 3 to 5 more feet away from them. Maybe go for a smaller speaker like a bookshelf. You don't need to get rid of your Sony. It's not the problem. 
@lowerdrive, There’s always the $3 Wal-Mart experiment. Buy a pair of white winter socks and hang them over the tweeters, see if that doesn’t smooth things out. Also. I think break-in is only an issue for tube gear.
I did not read all the previous replies, but You did quite the detailed write up for your equipment, but you left out the most important thing.  
What kind of music do you listen to?  

Many mass speaker manufactures try to impress you out of the gate so they design speakers to be very reveling on the top.  You can hear highhsts like you never heard before but after a couple of hours it’s painful.  Pop / electronic music suffers in many areas of SQ.  

I had purchased B&W cm601, impressive on top, but painful with my Puoneer Elite receiver.  
Replaced the receiver and sonos connect for Primaluna Dialog HP and Schiit Yggy DAC.  Still harsh with some female and poorly mixed and electronic instruments.  Acoustic music all wonderful.  Next replaced B&W with Aerial Acoustics 5T.  Ah ........ finally.

So, if you don’t want to spend 12k on a new system here are my suggestions:

1) Replace your digital sources with a TT.  That will effectively cut the digital harshenes you are hearing.

2).  Listen to acoustic music mostly. 

3).  Try Roon and Educate yourself on how to use a 3rd party software to apply convolution filter to improve the room Acoustics and EQ. 

Good luck