How much of a difference would .75 cu feet make?

[kozzmozmo 10+ year member]

Im in the process of building a box for my mustang but the problem is it's a convertible with limited space. I have 2 S12l7's that I'm going to build a couple boxes for in the trunk. The problem is I can fit 2 1.75 cu foot boxes in my trunk without losing function of my convertible top. If I go for the 2.5 cu foot boxes then I would lose function of the top. Does the extra .75 cu foot make that much of a difference in sound quality / spl to consider losing the function of my top? Or should I just make the 1.75 cu ft boxes? What would you do.

Edit : And If I was to build the 2.5 box and try to retain top function it would have to be a radically shaped box that would be very difficult to build and I would run into port problems..

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[97JeepTJ 10+ year member]

build both //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif ... use one in the summer times and one in the winter times //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[kozzmozmo 10+ year member]

lol good idea

 

[kozzmozmo 10+ year member]

god i hate building boxes. have no idea how to build a port that would be sloped, not rectangular shaped or even if it could be done grrr

 

[kozzmozmo 10+ year member]

anybody......................................

 

[kozzmozmo 10+ year member]

god ijma bout to spazz out **** boxes

 

[Einzee 10+ year member]

well to simply put it: You should always follow the manufacture's guidelines for installation. And i dont really know the technical stuff about internal volume and porting but i do know that if you sway very far from the "guidelines" you will compromise sound quality.

 

[squeak9798 5,000+ posts]

well to simply put it: You should always follow the manufacture's guidelines for installation. And i dont really know the technical stuff about internal volume and porting but i do know that if you sway very far from the "guidelines" you will compromise sound quality.

That's not really true. Most manufacturer's "recommend" smaller sized boxes because that is the sound that most "street beaters" prefer. Sometimes going bigger will actually improve the SQ.

I don't know anything about L7s, and I don't have my box program with me here at work, so I can't say exactly how much of a difference there will be.

 

[kozzmozmo 10+ year member]

Iv'e been playing around with my winISD and it dosen't appear to be very much difference, Kicker recommends atleast 1.75 cu ft. per sub and i'm going to have atleast that maybe more, will only know after box is built. I'm basically cutting the pieces and building the entire box inside of my trunk cuz thats the only way its going to fit and give ample room...I'll post pics soon, probaly later today

 

[kozzmozmo 10+ year member]

I know, the port is going to take up about .32 cu ft.* The 1.75 is going to be volume of my box minus port volume. What I'm doing is constructing a box inside my trunk, after the main box is built i'll figure out the exact volume within the box which will be failry easy as the shapes only consist of rectangles and triangles. Then I'll design a port that will get me the tuning I want and fit my box.

I'm also using WinISD .44 to help design the port. Anyone here care to comment how accurate it has been for you? When using it compared to the forumla on say jlaudio website it's generally about 1/2 inch off which probaly shouldnt matter because I don't really care if it's actually tuned to 37hz when I want 36hz. Maybe WinISD comes up with different numbers because It takes into account more variables then the other formula does.

On a side note how does a 10 X 2.5 inch port 12 inches deep sound? Would that possibley create any unwanted port noise. I think I read you want to keep atleast a 1/8 w/h ratio and the more square you can physically/ asthetically get the ratio the better?

 

[ANeonRider 10+ year member]

I know, the port is going to take up about .32 cu ft.* The 1.75 is going to be volume of my box minus port volume. What I'm doing is constructing a box inside my trunk, after the main box is built i'll figure out the exact volume within the box which will be failry easy as the shapes only consist of rectangles and triangles. Then I'll design a port that will get me the tuning I want and fit my box.
I'm also using WinISD .44 to help design the port. Anyone here care to comment how accurate it has been for you? When using it compared to the forumla on say jlaudio website it's generally about 1/2 inch off which probaly shouldnt matter because I don't really care if it's actually tuned to 37hz when I want 36hz. Maybe WinISD comes up with different numbers because It takes into account more variables then the other formula does.

On a side note how does a 10 X 2.5 inch port 12 inches deep sound? Would that possibley create any unwanted port noise. I think I read you want to keep atleast a 1/8 w/h ratio and the more square you can physically/ asthetically get the ratio the better?

What about the drivers? or are you inverting them?

 

[BASS OUTLAW 10+ year member]

Stop using WinISD Beta and get WinISD Pro ... WinISD Beta = Garbage ...

i find both of them hard for me :S //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

 

[kozzmozmo 10+ year member]

I have WINISD pro alpha I suppose i'll start to use that if you say it's better.