Works with Google playmusic app too. That's all I have
Sweet baby jesus I think you might be on to something here! This was my biggest complaint about the phone and couldn't figure it out. Bluetooth, aux, different devices, even just the speaker on the phone - they all sucked for sound volume and quality. I clicked the equalizer on and an immediate improvement on the phones speaker. I'm going to try it on my truck stereo ont he way home and hope for the best!
I ended up getting a standalone equalizer app since not every app has the equalizer built into the free version. I'm using Bass EQ and have definitely noticed the difference in sound quality.