Can someone please explain


What you mean when you say (whether it’s a speaker or amp or preamp) it’s darker or warmer or softer or leans to the brighter side of neutral? Are you talking about how ss compares to tubes to class D? Analog to digital? How do you know what "neutral" is? How do you not know it’s actually in the recording? 
Curious minds/ears want to know.
rsf507
A great example how an honest and  innocent question, in this case of sound quality can turn. From soup to nuts ....
@isochronism 
Don’t pay attention to distracting little details. The main point is congenital factor of sound perception.  
When I look at a painting I generally view it as a whole creation.....not individual components of paint colors/textures, tints, composition, view angle, etc. (abstract stuff too).
With music, for me, the same thing goes....and I either actively engage with it or don’t.
Hear the music and decide on a macro level or drive yourself crazy.
I’ll never be unequivocally sure what the artist intended and/or what happened in the daisy-chain between the creation and my ears.....but I do know if I like it or not.
I’ll probably be banned for saying this, but please try to ignore what you MAY be missing (really or not) and just enjoy the pleasure of experiencing the music with what equipment you’ve got.
please try to ignore what you MAY be missing
silly point of view. Ignoring the fact of subject existing does not cancel the fact. The person who just trust will never click  with person who try to understand.
When you listen to your playing music, you (rather obviously) are hearing everything working together - the sum total of what your equipment does to the the sound of the recording being played. One earlier commenter was completely correct: we are all at the mercy of the recording engineer. After that, we have some control. Acoustic instruments are a good guide to accuracy. It's pretty easy to hear guitars, ukuleles, banjos, mandolins, and the whole violin family played in a place near you. Go to amateur events, music club meetings, school presentations and such near you. Listen to the sound of the instruments, however well played (or not). Compare the sound of a banjo with a steel rim verses an aluminum one (aluminum is brighter as well as less heavy and cheaper, steel is darker, heavier, more expensive). How does a big bodied guitar sound in comparison to a smaller, more hourglass shaped instrument? Now play music recordings of those instruments and see how that compares to your memory of the live instruments. All of us have differently shaped ears. No two of us hear exactly the same thing, so the definition of "really good" equipment is always subjective. Don't be too concerned with someone else's opinion. Start with well reviewed (that does NOT mean expensive) equipment, perhaps bought "used" - read: save a bundle - and speakers that seem good to you. Speakers make the most difference in what you'll hear. The room you are listening in is the next most important factor. That's why headphones are so popular. Wires, fancy or otherwise, make the least difference. Many professional musicians never listen to recorded music because the sound is foreign to them. They put their money into good instruments. When you have a system sounds good to you, enjoy it and don't invite any critical people over to your house! Keep Smiling! Enjoy the music!