I'm no genius in the physics of sound but someone please explain this to me.

I was planning to building the well sump sub box. I usually have my sub on the backshelf behind the seats in a subzero nonported truck rider box. I stacked up some stuff in the trunk well to support the subbox back there. The same position it would be in with the well sump box. So I braced it up, closed the hatch, got in, turned on the tunes and it was like I added 2 more subs and another amp???

I loved the effect but couldn't drive like that. I sat it in the well with the sub facing the rear of the car and same thing just not as profound.

Why and how is my sub hitting 2-3 times harder in the different position? This unnerves me because I don't know the explanation.

 

That is the beauty of a hatchback, or so I have been told. The hatch makes a great reflector for the bass frequencies and sends them to the front. Someone else might explain better than me.

 

that simple or what

 

You're doing 2 things, you're compession loading, or using the subwoofers to excite the mass of air behind them rather than just what they can push aiming foward, and you're reducing cancellation from the waves hitting the front of your car and coming back. When the sub makes a tone it's omni directional, sound exits not only the front of the enclosure but also moves towards the rear. This sound reflects and at some point in your vehicle arrives out of phase with the foward wave. By turning the subs around you're aligning the wave from the back of the enclosure with the one that's immediatly reflecting from the front. If this doesn't make sense I'll try and find the write up on it online that has illustrations.

 

It makes sense. Even my friends thought I got a new system. Is there any risk of damage with this method?

 

if you have it in the same box running the same power and everything is the same.. no theres going to be no problem.. unless the sub is too close to plastics or the floor and is hitting them while bumping .. hehe

 

All true responses. The hatch is as mentioned and acting as a compression chamber to roll-off the soundwaves. It is actually making a slight efficientcy boost. If you have ever been invlved in any HomeTheatre setups, you would notice the sub is commonly placed toward a rooms corner. The lower frequencies rely on reflection to produce a higher dB. The walls of a room help aid in the reflection of the soundwaves. In setting up a HT system, it is actually harder to find a home for the sub and to get its 'sweet-spot' than a pair of towers and center channel. A car is the opposite. Because of most vehicles designs, the sub is easiest to place since the space and deflection walls are in a tighter arrangement.