According to some, inverting a subwoofer can help keep the speakers cooler and can help increase the box volume. However, most agree that doing this does not make your subwoofer louder. It can help with space issues though, allowing you to fit the speakers in an area with a smaller box that normally would not work.

Do subs sound better facing up or down?

Facing the subwoofer upward while in the trunk, gives you big bass without consuming a lot of space. This direction offers crisp sound with a slight advantage to high frequencies and treble, and won't rattle loose parts in your vehicle as much.

Do subwoofers hit harder facing up?

are to the face of the subwoofer, the louder it will be. This is due to the fact that the sound waves bounce off of the wall, or whatever it may be, and go throughout the cab in more than one direction.