The wave is the same length. The difference is the frequency you get the lowest null point at. In most cars, if the woofer is near the seat, the null point caused by the reflection off the back of the trunk is low enough to be in the passband of the woofer so you will hear it and can measure it. If you open the trunk lid, suddenly you have lots of bass. This is because the reflecting surface was compromised so the null disappeared. By your theory the only wave left with the trunk open would be the one from the woofer to the front and there would be no extra output with the trunk open.

The farther back towards the taillights the woofer/port gets, the higher frequency the null point happens at until it gets out of the passband and isn't a problem.

So the safest design is to either have the woofer/port as far back in the trunk as possible, or to seal off the trunk from the cabin.

 

Yeah I'm not feeling the wall anymore. Too bad, it's solid. It's gonna suck to take out.

Mebbe I'm gonna get me some sweet funfur seat covers for those

 

I could bring the sawzall over on the weekend.......I work for food.....

 

wow.. ok well put. I think I comprehend what you are saying. It makes sense to seal off the trunk from the cabin completely to avoid a null point at all. At this point the bass inside the cabin will not be effected by a trunk opened or closed.

 

Exactly. If you like the idea of seeing your woofers with the seat folded down then it is really important to try to seal off the trunk from the cabin the best you can.