I would try switching them/testing them to your liking,.Setting at -6db may not be the low end you want to listen too,as 0 setting should be a little bit higher pitch.I like to place the crossovers at the kick panels to have access to the crossover.Just try the different settings ,and listen to which sounds best to you, mild and smooth,or loud and crisp at you so to speak.Listen to one of your favorite songs, and listen to which setting you like and leave it at that.