box design for 1991 honda civic

6thaveme wrote: Thanks for the advice i kinda figured i would never get 4 15s in the trunk of a coupe.Im going to get a new car soon and keep my civic on the road for competion so a wall seems very intresting....Im nervous that with the wall in my car there wont be enouph back pressure for the subs to sound good does anybody no how the wall will do on a meter.....

are you talking about using the trunk as the box? is that why you mention back pressure? building a wall is not really different from building a normal box. its still completely enclosed except for the port. you design it so that it fits in whatever car you want and tune it to just below the frequency you want to burp in competition. the output you get from a wall depends on a lot of factors but the main ones are: efficiency of the box at the burp frequency, power, cone area, physical box strength( any flex is lost output), and strength of the vehicle itself. this is why most high spl vehicles are filled with reinforcing struts to keep the walls and roof from flexing under high pressure.

What i meant to say by backpressure is bass reflection.For instance when i had my box laying on my back seat instead of my trunk i got felt the bass much more when the sub was fireing twords the side of my car compared to the sub fireing twords the front of my car.That tells me the bass waves are bouncing back much faster when the box is faceing twords the side of my car because the bass waves have less room to travel.So if i walled off my car my issue would be that the bass waves would have to stretch out further to reflect off the front of my car..4 12s cvr sealed

2 hifonics bxi608d

1 kinetic hc 800

alpine reciever

infinity kappa door speakers

well, you can feel more bass but its not necessarily louder on a meter. it is possible to feel or hear a difference when you change the placement of a sub but that is mostly due to the difference in distance that the wave(s) have to travel to make it to you. thats why you might get completely different results from facing the subs towards the back of the trunk instead of towards the front, but that can go either way depending on the design of the box. and bass waves dont "stretch" under normal conditions, the wave length is set depending on the frequency. and it would be hard to give you an answer about reflections in your car because different materials either absorb or reflect or resonate certain frequencies. in an ideal setting you would want everything to absorb to get the best sound quality but if you can get your hands on a RTA you can measure what frequencies get resonated and tune your wall to that frequency to give you an added bit of output. this is what the real high output competitors try to do, they use everything to their advantage.

6thaveme wrote: What i meant to say by backpressure is bass reflection.For instance when i had my box laying on my back seat instead of my trunk i got felt the bass much more when the sub was fireing twords the side of my car compared to the sub fireing twords the front of my car.That tells me the bass waves are bouncing back much faster when the box is faceing twords the side of my car because the bass waves have less room to travel.So if i walled off my car my issue would be that the bass waves would have to stretch out further to reflect off the front of my car..

waves bouncing faster?? The speed of sound does not change from the position of the enclosure.Custom Enclosure Design

Depends on the enclosure and the install...Can't say that with any certaintyCustom Enclosure Design

just had a thought, i have no idea if it is true or not but maybe with the sub hitting closer to a wall it puts more energy into a wall and some of that energy gets transferred throughout the entire car by the walls thus turning the whole car into a speaker through the walls vibrations. but, i really dont know, its just a thought.