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.

  • 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.

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


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.)
When I worked in QA they told us "You can't fix what you can't measure."

So start by getting the Real Time Analyzer app for your smart phone and do some measurements.  My recent listening rooms have been on the small side with lots of plaster/sheetrock and bare wood floors.  

When measured (I used MathAudioRoomEQ and a RatShack digital meter) there's a +15db peak centered around 7khz.

Knowing what the problem was, I could fix it with EQ.  If I owned rather than rented, I'd have used room treatments as some are advising here, but the point is, I knew what the problem was.\

Take some measurements.  See where the problems are.  Then ask for advice again.
One of the best quotes I've seen about audio gear that has helped me understand how things interact is "the volume knob on an amp is like the focus ring on a camera". There's definitely a sweet spot with an amp/speaker combo where things come alive a bit more, sometimes it's a broader range than others but in my experience bigger speakers usually make me want to turn up the volume to hear them at their best. At which point a certain significant other turns it down again.

Speakers vibrate the air around them and bigger speakers vibrate more of it. Those vibrations interact with the walls, ceiling, floor etc and cause issues. As you've found, smaller speakers often work better than bigger ones in a small room. The important thing is to match your setup to your preferred listening level in the particular room.

There's a harshness associated with digital reproduction and also sometimes around the crossover frequencies of speakers. I've found having tubes somewhere in the chain helps, before I switched to a tube pre/power combo I tried an ifi itube tube buffer, which definitely got rid of a lot of the annoying harshness in the upper mids. 

@corparehippie  "There's a harshness associated with digital reproduction".  That certainly is true up to a point of quality (which we're obviously dealing with in this case), but the upper echelons of today's digital reproduction have no such harshness and are frankly, unparalleled by any other sources.  Check out an EMM Labs DA2 with V2 firmware (or based on reports, the top of the line MSB DACs).
To be honest, I have never noticed such harshness, even using modest digital sources in a revealing system. There is clarity compared to vinyl, which is not surprising if you look at the high frequency drop off in plots of many pickup cartridges. Reality takes getting used to.
If there is harshness, it is usually either the speakers or a reflective room. One other thing could be clipping distortion on the input stage of the amplifier. Most digital sources conform to the Red Book standard of 2.0 Volt output, and that is a lot for the line input of many traditional amplifiers. Amplifier designers would do well to take notice, but if they don’t, inline attenuators are the easy cure.
@willemj It really depends upon what we’re talking about. Most of the low to mid audiophile digital isn’t harsh because it’s artificially smooth and lacking in detail retrieval and dynamics. In that regard, you are absolutely correct in that most audiophile digital these days is not harsh, but it is lacking in many other ways. If that same digital actually revealed the detail that’s there in a proper system that is capable of revealing such detail, they would certainly be quite harsh almost across the board. But this is all besides the point here; in this case we’re talking about a blu ray player and a receiver - that’s quite low end and is going to be harsh in almost any system (it certainly also doesn’t help that the OP is using four speakers for two channel - that can’t help, not to mention that such speakers are low end to boot).