By following this guide you will be able to separate our Discord and Music audio in different virtual cables, so before starting make sure to download the virtual audio cables from here:
Open VBCABLE_A_B_Driver_Pack43.zip file.
Drag VBCABLE_A_Driver_Pack43.zip and VBCABLE_B_Driver_Pack43.zip into your desktop
Extract every one of the zip files into a separate folder
right-click on the zip file → Extract to “zip file name”
Open each folder and run VBCABLE_Setup_x64.exe so we could have 2 virtual audio cables installed.
Go to your settings → Voice & Video → change the output device to CABLE-B Input(VB-Audio Cable B).