I have a JL 10W7 in a JL ported enclosure..... i've placed it in the trunk of my car with the sub firing towards the back of my trunk (like most...) What would be the dis/advantage of positioning the box so the sub fires upwards OR towards the seat.... right now i have to keep the door to the trunk (behind the rear armrest) to get the full effect of the sub...

 

I believe it is better to fire towards the rear so that the waves can reflect of the rear, giving them more space to fully develop, so you will get slightly lower bass backfiring versus forward firing

 

it depends on so many factors that the best way to tell is to use your ear and try different positions. I prefer facing back, but factors such as your enclosure dimension and other items that may be in your trunk are all going to affect the sound.

 

subs positioned towards rear of car, firing upward.