Yep, had the same in my One; but the sound does get louder in small steps when you increase speed; too bad you cannot adjust. My partner has a COOPER without the Harman/Kardon and there the menu appears for setting the speed volume, so it has to do with the way the H/K is linked to the Boost head-unit. Did not bother to ask dealer as they most likely do not know how to fix.BT1 said: