(Android) $0 FREE Equalizer FX. Pro (Was $2.49) '@ Google Play

Rated 4.2 with over 100k downloads and no IAP.

The Equalizer FX allows you to improve sound quality of your android device to get more to enjoy of listening music.
The application Equalizer FX lets you adjust the sound effect levels so you can get the better out of your music.

Application includes:

• Equalizer. Audio filter to change the frequency envelope of the sound.
• Bass boost. Audio effect to boost or amplify low frequencies of the sound.
• Virtualization. Audio effect to virtualize audio channels. Allow you to enhance stereo effect.
• Loudness Enhancer. Loudness Enhancer is an audio effect for increasing music loudness. (Only for Android 4.4 and higher)
• 12 presets. Also you able to create your own presets.
  The application works with music players and audio streaming services like Pandora, Spotify, TuneIn Radio, VK, etc.
• Equalizer Widgets for your home screen.
• Automatically on/off when music player starts/stops playing music.
• Flexible configuration.