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
erik_squires: "This is why I think so many audiophiles should make at least one pair of speakers in their lifetimes. It would completely reset their expectations of money and value." That's an idea I really like! Thank you.


itsjustme: "I tend to agree that you likely have too much stuff, of too little quality, with too small a room, but proceed logically, step by step." I agree now too. And yes, I will proceed step-by-step. My goal is to learn and gain experience before I start spending a lot of money.

" I know you were asked, but why do you have four sizable speakers?" I started off with a 7.1 configuration. When I realized 7.1 was too much for this room, I tried a 5.1. That left me with two spare speakers, so I experimented.

"To get an objective view of what;s going on maybe you can find a local audio geek with a doppler or pulse spectrum analyzer." That interests me, but meeting trustworthy experts takes time. I hope I can do what you suggested, but I don't know how quickly I'll meet the right audio geek. I only started this project a couple weeks ago. :-)
I too am on a budget over here. The speakers I've got are really the prize pieces of the stereo cost-wise and I picked them for their sound AND the fact that they're extremely revealing of upstream gear. That characteristic suggests a very high degree of neutrality and transparency. I spent the money on them because I'm quite certain there's no possible way for me to have built anything that comes close to them for anywhere near the price. Everything upstream of the speaker's terminals was either built or rebuilt by me with the exception of a couple of interconnects. That's saved me a big pile of money. Who else here is enjoying 50 watts of Pass power for under $1000? That's what I'm talking about. 
My advice going forward is learn, learn, and learn. Understand the specs. Understand what impedance is and what it does at different stages of the audio chain. Learn modes of operation for gain devices. Learn basic topologies. Seriously consider building what you can. Cables are easy to build. Some amps are very easy to build. Buffer pre-amps are easy to build. I'm learning that Raspberry Pi-bases DAC sources are actually quite easy to build. My only complaint with Eric's suggestion that folks build speakers is the cost of acquiring a wood shop if you don't already own one. On the other hand, you can build a stunning amp with not many more tools than a screwdriver, a cresent wrench, a soldering iron, and some wire cutters. 
kosst_amojan - if you said which speakers you own, I missed it. I'd like to know. THanks.
Focal Aria 936's. I started out powering them with a 40 year old recapped Marantz. Last year I built a muscled up Pass F5 which is a very good match to them. When I began building the amp I'd planned to immediately follow that up with a unity gain buffer pre-amp. Other things have come up. 
I like the 936's a lot. They're very smooth, image excellently, and are transparent to the electronics driving the. The F5 is a very wide bandwidth (DC-1MHz) class A push-pull Nelson Pass design noted for it's muscle, accuracy, and merciless transparency.  My build it a bit more muscular than Nelson's First Watt product. 60 watts of clean class A power is gobs of power. It's a good match to the reactive load the Focals provide. The Focals aren't everybody's cup of tea, but I think they're excellent given my tastes, ideals, and long term plan. 
If you want to know more feel free to PM me. 

For 2-channel listening I'd recommend a tube amp, room treatments, and possibly speaker toe-in/out adjustments. Borrowing a partial quote posted by a very knowledgeable man from another thread touting an advantage of employing a tube amplifier ...

although solid state amps appear to have less distortion, the distortion that they do have is far more audible and objectionable to the human ear.