Here’s what you should probably know about iPhone music tweaks.
The instructions in this article apply to iPhones runningiOS 11and higher.
These controls offer different audio playback styles.

If you want to increase the bass sound of your music, chooseBass Booster.
Listen to a lot of jazz?
Get just the right mix by choosing theJazzsetting.
Listening to a lot of podcasts or audiobooks?
Pick theSpoken Word option.
The Volume Limit setting addresses that by limiting the maximum volume of the music on your equipment.
To use it, go toSettings>Music>Volume Limit.
Move theMax Volumeslider to the loudest you want your music to play.
Those steps are for iOS 12.
On earlier versions of the iOS, go toSettings>General>Restrictions>Volume Limit.
TapVolume Limitand selectDon’t Allow Changes.
Sound Check works in iTunes, too.
To learn how to enable it there, check outHow to Enable and Use Sound Check in iTunes.
But that’s the only option.
It also lets you add star ratings to songs for use when creating smart playlists.
The Star Rating option is hidden by default in iOS 12 and up.
Turn it on by going toSettings>Music>Show Star Ratings> moving the slider toon/green.