To get good audio, you start by recording at a low enough level (pre amp setting) that you allow for 16-18 dB of headroom (where your peaks only go that high).
Then you mix your tracks so the average level is somewhere around -12dB
Then you master your tracks to the peak level and average level in LUFS appropriate for the medium (vinyl, CD, tape) or streaming service you are using for distribution.
For Spotify, you use -14 LUFS.
For SoundCloud use want a peak level of -1 dBTP and -8 to -13 LUFS
Here's one of many web sites with more details and a deeper explanation:
https://www.masteringthemix.com/blogs/learn/76296773-mastering-audio-for-soundcloud-itunes-spotify-and-youtube
Steven
