No ads, no popups, just the Equalizer itself at 14kb to boost the bass, increase the volume of certain frequencies and improve the overall sound quality.
MOTOROLA ANDROID 5 NOTE: I've had several people contacting me about the app not adjusting any sound at all, I don't own any Motorola devices so I couldn't investigate this one my own yet. I tried a couple of other equalizer apps on a friends' Moto G and none of them seemed to works so it appears to be a global issue.
I hope we will find a way to get around this, stay tuned.
Project based on http://kevinboone.net/android_simple_eq.html uploaded with his consent.