I love playing KR games, and I love listening to music. But I cannot enjoy the two together. There's no way to lower the volume of the SFX nor the voices. I suggest Ironhide spend some extra time trying to play the game while listening to music, the loud voice acting and SFX make up for an unpleasant experience.
And this goes true whether I am using external bluetoith speakers, or bluetooth headsets, or just my iPad Air 2 speakers.
I hate to do it but every time at I wanna play KR I must turn off the Sound for the game, just to enjoy some music.