It’s very simple: normaly, at the front, you have the singer, guitar/ piano. Back there: other Instruments:violins,orchestration,.. At the very back: drums, (percussion).. With a good recording, you hear: 3D:You Can hear where the instrument is, more in the foreground , some more behind it. Voice, guitar,piano have approximately the same frequency: between 300 and 800 hz. If they are recorded and mixed at the same volume ,gives that a kind of resonance. It gives the impression that it is mixed up. Gives a bad feeling in the ears. The last one of Sarah Brightman is such a bad recording, as her voice comes all the way from the back. That’s the reason why ,you have good and bad recordings. The better your equipment, the more you will make a choice in your music. Ultimately you will listen to the less good (or bad) recordings much less because it irritates your ears.