A free program for Android, by FrackStudio.

Improve the sound quality of your Android device with the app Equalizer & Bass Booster – XEQ. This app is very easy to use and is packed with professional features. With this, you can use the 10-brand equalizer, sound booster, and bass booster. It also has a virtualizer for a 3D effect.

This app will also allow you to create a specific preset for every device that you use for playing music. It also features Spotify Integration, so it reads song information and controls the track on Spotify. Aside from Spotify, it is also compatible with Apple Music, Youtube, Amazon Music, Tidal, Pandora, and more.