Port Breathing Room

[Thewes]

From the back of my seats leaned all the way back, to the back of my hatch, is roughly 47 something inches. Now my box design is 40 inches, giving it 7 inches or less of breathing room. It is a huge 6x35 slot port in the back. I've heard different things about ports and their breathing room, just curious how I can take care of this.

[SPL2K]

From the back of my seats leaned all the way back, to the back of my hatch, is roughly 47 something inches. Now my box design is 40 inches, giving it 7 inches or less of breathing room. It is a huge 6x35 slot port in the back. I've heard different things about ports and their breathing room, just curious how I can take care of this.

7" of room is fine for a 6" X 35" port.

[Thewes]

7" of room is fine for a 6" X 35" port.

How much distance should I start to worry? It might be a little bit less.

[RiddleRampage84]

That is a good ? I would also like to know how much is not enough...

[SPL2K]

How much distance should I start to worry? It might be a little bit less.

well the closer you are to the size of the port ( 6" ) the more it will start to act as an extension of the port and lower your tuning. As long as the box isnt already tuned real low it wont be a problem.

[Thewes]

well the closer you are to the size of the port ( 6" ) the more it will start to act as an extension of the port and lower your tuning. As long as the box isnt already tuned real low it wont be a problem.

Im not sure if I'm explaining my port right. Its 35 inches in width, its 6 inches in height, and it extends 20 inches into my box (atleast, Im not sure on this yet)

[SPL2K]

Im not sure if I'm explaining my port right. Its 35 inches in width, its 6 inches in height, and it extends 20 inches into my box (atleast, Im not sure on this yet)

yes. You are explaining it right and i understand. If your port opening is 6" tall (regardless of depth and length) and the edge of it is 6" from your tailgate or back of your car then the area between the tailgate and the back of the box becomes an extension of the port which will tune your enclosure much lower.

example....

if your port is 20" long and the box is 18" tall then you port is now actually 38" long

[Guest Dylan Dude]

Im not sure if I'm explaining my port right. Its 35 inches in width, its 6 inches in height, and it extends 20 inches into my box (atleast, Im not sure on this yet)

yes and he's saying you don't want to be near the smallest dimension, which would be 6" in your case. Because then the back wall of your hatch will start to act like the port wall.

[Decaf]

so yes you will loose output.... but gain low end extension... and what u loose isnt much

it would be the equivalent of tuning ur box lower

ie: instead of it going 20" into the box at least, the subs would (for hypothetical purposes) think the port length increased, thus lowering tuning and as long as u arent tune to 30hz or lower, u shouldnt notice much

and if you do its in the higher frequencies, but u will have a smoother rollof into ur midbass

edit* - i hate when three of us answer at once the same answer lol

Edited April 18, 2008 by decafcappucino

[Thewes]

so yes you will loose output.... but gain low end extension... and what u loose isnt much

it would be the equivalent of tuning ur box lower

ie: instead of it going 20" into the box at least, the subs would (for hypothetical purposes) think the port length increased, thus lowering tuning and as long as u arent tune to 30hz or lower, u shouldnt notice much

and if you do its in the higher frequencies, but u will have a smoother rollof into ur midbass

edit* - i hate when three of us answer at once the same answer lol

Thanks SPL2K and everyone else, appreciate it.