inverted sub/ box help

[Chris661]

what'up

im in need of help.Is my Box design correct? errors? anything should i change

sub is going to be inverted

btl.18

thanks

-Chris

[bassl0va]

If that drawing is to scale, then the port is too small. But thats only if it's not to scale.

[CaptainzPlanetz]

I think that box would be around 5.6cubes after displacement, with 100 square inches of port, which equals about 17 square inches of port per cub, which is fine. Someone correct me if I am wrong.

[fecupe2001]

How come the ports it´s too small?? it´s 100SQ, i think this box it´s ok, but the tuning it´s way too high, if i´m correct, you are getting 45 hz tuning on that box with 18SQof port per cubic feet, 5.5 c/f after displacement.

If you are looking for a lower tuning, then you don´t need a port that big, unless BTL really likes giant ports (haven´t use one before) , i would get a port 5x15x17 giving me 39 hz of tuning, 13.5 SQ of port per cubic feet and 5.8 c/f after displacement...

[Skullz]

Copied from the FI site.

BTL 18 – Ported box we recommend using 5-8 cubic feet @ 30-35Hz tuning, you can tune a little higher if you wish but we recommend keeping it close to 32hz for a daily driver. Again the same 12-16 square inches of area applies per cubic foot of volume.

Your port would need to be 4x16x24 for a 32hz tune from the box with a displacement of .1 for any bracing.

[fecupe2001]

Dude, not always you have to go with the manual, depends on the kind of music you like, DD recommends 35 hz tuning and i tuned to 41 hz so i didn´t lose the highs, more than happy with the result!! Just because Fi says tune to 32 hz doesn´t mean everybody listens just that kind of music, besides that, if he get the port that big (talking about the length), he is shrinking the box, would give him around 11.5SQ of port per cubic feet, maybe the 12SQ of port, but i prefer a little bit high on the tuning and some more output with 13.5SQ of port per cubic feet, but that´s just me of course.

Said all that, it depends on his music likes of course, not ours, i can asure you that my next box for 2 18" it´s gonna be tune around 32 hz just like you told him

[Skullz]

Well we both could be wrong and he was building a comp box but since the purpose of the box isn't known its just a matter of guessing on whats being done here.

[fecupe2001]

hehe well said, thinking now, i guess you must be right! if he´s looking for 45 hz tuning and 5.5 c/f feet that doesn´t sound like a daily box at all, touche! hehe, cheers...

[Chris661]

If that drawing is to scale, then the port is too small. But thats only if it's not to scale.

yes it drawin to scale.

How come the ports it´s too small?? it´s 100SQ, i think this box it´s ok, but the tuning it´s way too high, if i´m correct, you are getting 45 hz tuning on that box with 18SQof port per cubic feet, 5.5 c/f after displacement.

If you are looking for a lower tuning, then you don´t need a port that big, unless BTL really likes giant ports (haven´t use one before) , i would get a port 5x15x17 giving me 39 hz of tuning, 13.5 SQ of port per cubic feet and 5.8 c/f after displacement...

so i would be fine with 5x15x17 ? 39hz?

it going to be a daily beater. and iverted sub.

[fecupe2001]

Yes, i think that would work just fine, to be precised, 5.7 cubic feet and 13.2SQ of port per c/f , you would have 39 hz of tuning, big problem is that you haven´t got any bracing inside the box, that would also shrink down the internal space raising your tuning also, try at least to get double baffle!