Another great discussion about loudness and mastering in the Mastering Audio in Logic Pro X Course.
My advice for loudness where the culprit may be an unbalanced mix...
When you are mixing, make sure that the DR (difference between peak and RMS) is healthy. If it's too small, it may be that you have an unbalanced mix. This is common when the bass is too loud. Our ears are less sensitive to bass, so when a mix is too bottom heavy, the bass eats up all the headroom and mastering can only do so much.
Balance is key to all of this. If you keep a healthy range between peak and RMS (like 10dB), your mix will likely end up more balanced, have greater punch, more clarity, and fulfill it's full loudness potential in mastering.
Balance is the key to loudness.
Hope this helps.
