Answer to "Why playing via AUX cut's on quiet passages in the songs/movies?"Hi, dude! I had the same problem with my JBL flip 4, but i know how to solve it. Try to set max volume on your device and then set optimal volume with +/- buttons on speaker. If the sound from connected device is low, flip 4 is cut it out. I don't know why, but it is so. I hope that I helped you.