There’s an issue that people who’ve started making music the past 10 years or so think an audio spectrum / waveform = what you hear. The sad fact is that it doesn’t.

One thing I’ve found that seemed to be a key to “professional” audio mixing / mastering people is that they had some kind of experience with real, studio mixers. They didn’t have access to spectrum windows, they mastered by tweaking dynamics knobs and using their ears. They didn’t have techy BS of calling out kHz or Hz numbers like “4,200”, “31.5” or other crap relating to decibel ranges like people using computer software so frequently do. This is because…