HELP! T/S parameters on fi btl 18's arent correct?

[M82a1snake 0]

i just ordered two fi btl 18s fully loaded like two days ago and have been researching all about them great subs is what ive been hearing, but im going to build my own ported box for them and have tryed using the t/s parameters listed on fi's website and i plug them in my bass box pro 6 and my winiSD and the programs basically end up saying that fi's t/s parameters are incorrect, because after ive typed in all listed parameters it says recommend internal size 5.25 cu. ft for two of the 18's i dont know whats wrong... and what do you guys think would be best box design and port design for 2 btl 18 fully loaded dual 2 ohms, 4 hifonics brz 1700.1D amps (amp per voice coil) ((dont worry gunna tune amps with O-scope)), 4 yellow top optimas all zero gauge back, high out put alt (not sure which brand and what the amperage should be yet), here is the room i got to work with for a box at max (externally) i basically measured for up fire but i dont know if that would hit the hardest compared to rear fire or walled off, 45" box width x 33" box depth x 23.5" box height. and i wanted port tuned to 32 hz. so if any of you guys know a better program or if you guys think its just the wrong listed fi btl 18 t/s parameters, in advanced thanks for all and any help.

[M82a1snake 0]

OH and i forgot to say ill be using 1" mdf all way around with quite some bracing inside.

[mr.sagat 10]

When using BBP6, don't go by what it recommends. Mine is usually retarded with it's likes/dislikes. Also, make sure the T/S specs in BBP6 are set the same units type as the btl specs you are entering. What I mean is, make sure they are metric or american. Just click where the spec is listed, to change it's unit type

[Cthedinger 2]

Man I am telling you now you are going to need way more batteries than that.

Edited June 3, 2010 by Cthedinger

[thebiggmann12 14]

Edited June 3, 2010 by Brandon Daily

[M82a1snake 0]

so brandon by looking at your calculator looks like you have the port positioned vertically while say if i do up fire(as in external box specs are still 33" depth, 23.5" height, and 45" width with subs on the top on the box. how & should i do that?? and you honestly think ill need more batteries? like how many would you estimate? cause im running all the amps at 2ohms which in theory it wouldnt drain or suck as much current at one time..

[M82a1snake 0]

basically im not sure how to explain it, but up firing subs as in subs mounted on the peice of wood that would be cut out to 45"x33". if that helps any...

[thebiggmann12 14]

well going subs up and port back you would have to have some space in between the port and the trunk/hatch u will be losing alot of space and would probably be pretty close to the bare minimum by making the back smaller. it would have to have a depth of somewhere around 27-30" instead of the 33". personally i would just do subs and port up.

[thebiggmann12 14]

o u want the port along the bottom of the box firing to the rear?

[M82a1snake 0]

ok ill take your opinion on it, but saying i do it subs up port up, how do i fit both subs plus an 8" port also on the same side (aka TOP Peice of wood) ...?? because if the top peice of wood is 45"x33" so therefore when box is together ill have 43"W x 31"H total for usable space.. sub cut out is 16.75" and the sub rim is 18.75" so take sub cut out (both subs) 33.5" thats only 9.5" left and if i wanted a 8" port i'd have no room...?

[thebiggmann12 14]

o good call, u could go one sub in the top right corner and then the other sub in the bottom left corner. that would probably save u a few inches, or i can re design and figure something out to have the port facing the rear.

[M82a1snake 0]

thanks lol. but yea if you could that'd be helpful! cause thats the problem is i dont know exactly where i want the port, i was thinking on the side of the box maybe also, like subs up firing and port coming from the side wall and goes underneath subs parallel with top and bottom peice of wood on box, but i dont know haha thanks for your help again!!

[thebiggmann12 14]

here take a look at this. still subs and port up. but fixed a few things. comes out to just a hair over 6 cubes per sub. slap some bracing in it (which you will need) and it will be right around 6 cubes even.

[thebiggmann12 14]

let me whip one up with subs up and port back.

[M82a1snake 0]

by the way i was thinking to do it subs up port up but subs like offset so they get more room i just dont know how to do the math on that one and basically i dont know how to figure out how much space i gain from that. hah

[Julian 641]

This is why you don't use Winisd on Fi woofers, use the recommended enclosure specs.

[thebiggmann12 14]

here is subs up port back. gives u 3 inches from the hatch/trunk, its only about 5 cubes per sub, but with the power your going to be running i dont think it will b a problem. lots of port area which is a good thing.

Edited June 3, 2010 by Brandon Daily

[thebiggmann12 14]

what do you mean subs offset?

[M82a1snake 0]

by the way with that last set up you gave me while the port up subs up, port at 5.5" (remember, only the sub cut out is 16.75, the actual ring around the subs is 18.5") and just using the sub cut out which is 16.75 each equals 33.5" and actual size of piece of wood on top including everything ill only have exactly 1" inbetween the outside port wall and sub cut out and 1" inbetween sub to sub cut out and 1" inbetween sub and wall.... which means it wont fit because actual size of ring for mount the screws in the sub ring measures at a diameter of 18.5"....

[M82a1snake 0]

subs offset (not out of phase or anything) i just simply mean not everything not in a linear line as in port vertical and two subs straight across , as compared to port vertical and subs diagonally alined.

[M82a1snake 0]

ok new calculations look good, but i see a flaw, which is ok external 45"W x 33"D x 23.5"H works fine... no need to shorten depth down because your calculations are basically for the side, inwhich you'd need to shorten width if it was placed port on bottom of the side peice of wood (subs up still).. right? and you think i need 3" in front of the port for breathing room?

[M82a1snake 0]

and do you think with that small of a port compared to the length i think the ratio is like 9 to 1 if its 9 to 1 or 10 to 1 or higher ive heard that port noise will occur. also with all those box specs and port specs do you think the woofer would be unloading? because i rlly cant afford to mess the woofers up ya kno?..

[M82a1snake 0]

by the way this is going into an suv, a chevy trailblazer, if that helps any.. thank you all for all the help!!!

[///M5 2,833]

A couple clarifications.

1) The T/S parameters are not wrong, you are using the software wrong.

2) NEVER EVER use a recommended enclosure in ANY software package, in particular if all you have put in are the T/S parameters. That only is a small piece of the puzzle, not the complete picture and it will lead you down a very wrong path.

3) Considering both 1 & 2 alluded you, you really, really, really, really, really should just build to Fi recommended specifications.

[NDMstang65 403]

A couple clarifications.

1) The T/S parameters are not wrong, you are using the software wrong.

2) NEVER EVER use a recommended enclosure in ANY software package, in particular if all you have put in are the T/S parameters. That only is a small piece of the puzzle, not the complete picture and it will lead you down a very wrong path.

3) Considering both 1 & 2 alluded you, you really, really, really, really, really should just build to Fi recommended specifications.

^^

We might just possibly know what we're talking about with the whole guidelines thing. If you build it outside of the guidelines don't be surprised if it sounds horrible

Box programs suck.