How To Install Master Presets On Logic Pro X & GarageBand
READ FIRST BEFORE WATCHING VIDEO:
First, place the master presets in this folder: /Users/*yourusername/Music/Audio Music Apps/Patches/Output
Then open up Logic or GarageBand and in the top left menu bar click Track > Show Output Track (Logic) Show Master Track (GarageBand)
Select the Master Track, then open up the Library by clicking button in the workspace's upper-left corner. You can also use the keyboard shortcut "Y" to open the Library.
Navigate to User Patches > *select your master preset
Enjoy!
*the video below is for vocal presets not master presets, only including it so you can see the general process, but there are some key differences as mentioned in the steps above