Harsh High Frequencies on Speakers

I’ve read a lot of the responses to the post about harsh high frequencies, but have not seen one that fits my issue. Strings, piccolos and flutes sound harsh and metallic when I play classical music from my Samsung CD player, or when streaming classical music from my iPhone or MacBook via bluetooth, Airplay or Apple TV to my Yamaha Aventage RX-A2070 AVR. The speakers are SVS Ultra Towers. I had the same experience with Klipsch RP-280F towers. But in each instance when I listen to classical music from any public TV broadcast, or from any music and/or video app on my TV (Netflix, Amazon, PBS, Apple Music, Pandora, etc.), THE STRINGS SOUND PERFECTLY SOFT, close to what they sound like in a concert hall! I have the iTunes equalizer settings set to "flat" on my iPhone and MacBook. The Parametric Equalizer on my AVR is set to YPAO:flat. All music sources are going through my AVR. Does anyone know why the harshness exists from some sources and not from others?
After I posted this thread, I went into the iTunes equalizer and lowered the decibels on the higher frequencies.  Wow!  What a difference!  The strings, piccolo, and flutes sound natural now!  I am leaving this post in place for those who may find value in this.