A free app for Android, by Mobile_V9.

Bass Booster & Equalizer is a free Android app that lets you improve the sound quality of your Android device. This app is a music player with an equalizer, and it also includes a bass booster, so you can get the best sound. This app can be used with most music players and audio sources.

This app lets you choose from a variety of sound effects, including Normal, Classical, Dance, Straightness, Folk, Heavy Metal, Hip Hop, Jazz, Pop, Rock, Acoustic, Bass Boost, Treble Boost, Vocal Boost, Head Phone, Deep, Electronic, Latin, Loud, Lounge, Piano, RB, and more. You can choose the best effect for your music or video.

You can adjust the sound effects to get the best sound.