Hi, like I quoted above which worked for me:
1. Go to Settings
2. Select Apps
3. Select the 3-dots on the upper right, then select Show System
4. Find and select the MusicFX app on the list
5. Then select Storage
6. Then select Clear Cache, then Clear Data
7. Now, go back to Google Play and select Equalizer settings, and it may be already available to do your adjustment settings.
8. I hope that helps, if not, research further on forums, I guess...