I’ve been playing with settings in Spotify and thanks for pointing them out. I’ve found the simplest setup for perfect drum volume control over Spotify music, running GarageBand in the background on same iPhone.
See images below:
Simply go to the same settings section of Spotify from the YourLibrary tab, and change Playback to “Quiet” mode (default is “Normal”).
Restart Spotify and settings take place.
Now in GarageBand, Track Control - Output - Track Volume, has perfect levels to compliment the music. Eg Full Volume: drums clearly sit out louder than the music.
Or around 3/4 volume I find has the perfect balance but still clear drums above the music.
Ie no need to use Equalizer in Spotify or GarageBand. Once Spotify is set to Quiet, just adjust the GarageBand Track Volume for balance, and the Volume on the side of your phone for Master Volume.
Hope this helps, thanks again DrumPacker.