Can someone please explain

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!