So now my setup on my HTC One is Viper4Android FX, Viper4Android XHiFi, ExtremeBeats Studio, and Dolby Digital Plus. On my Note 3 i have Viper4Android FX, Viper4Android XHiFi, ExtremeBeats Studio 2.0, Pon-3,and Dolby Digital Plus. Music just sounds so awesome whether if I'm listening from my Skullcandy earphones, my speakers and sub in my room, or in the car. Vocals are clear, music is clear. you can hear the high, mids, and lows. Makes cars sound like they have a system. Even the phone speakers are louder and clearer. HTC One with soundmods:
Galaxy Note 3 with sound mods:
HTC One with Viper4Android:
The videos don't do the phones justice but you can get the idea