The crossover for the separates divides the sound and sends the proper spectrum of frequencies to the speaker designed to reproduce the specific notes. When separating the highs, mounting can be an issue. If you separate the speakers too much, the projection of sound from each speaker can confuse the sound direction. If the tweeter gets mounted close to your head, such as on the A-pillar, the tweeter can be attached to the terminal that is marked "-3dB." This will reduce the gain level of the tweeter so it doesn't overpower the mid.