Fi n2 12's 4th order huuuge

[noser7]

Ok guys got a 90 ranger planning on running 2 fi n2 12's in a 4th order running 6cb.ft sealed and 12cb.ft ported after displacement. Reason for the huge box is id like to get a 3rd fi down the road and not need to make another box.

My questions are

1) i want aeroport, i need to know the correct way to tune this box

2)bracing?

I would like to make it myself because i am broke and just have enough for wood glue and screws ? i just need a point in the right direction. Thanks for any help guys. Also......... i just want to do hairtricks daily

[noser7]

I forgot, since its 12 ported and 6 sealed what ratio does it make this box? 2:1?

[CleanSierra]

Ratios aren't a way to figure out how much ported space you need. So eventually you'll have 3 subs in 6 cubes total. Is 2 cubes per sub too much per sub? I mean unloading is a bitch from too much sealed space.

Do you know how much port area you'll need? Do you know how to design a 4th order bandpass?

[noser7]

I have read a couple articles on how to build a 4th order box.

They said use the company recomended specs for the sealed side, FI claims 1.5~2.5 i think 2 is a good number right? Also ive read a good tune is right around 45Hz.

What do you mean unloading is a bitch? Bottoming out the subs?

[noser7]

Oh and no i dont know how much port area i need, i need advice on all of that bro's. Id like to get my hands on this project. Im prety handy so i think i wont mess up with the right advice, thanks.

[CleanSierra]

I have read a couple articles on how to build a 4th order box.

They said use the company recomended specs for the sealed side, FI claims 1.5~2.5 i think 2 is a good number right? Also ive read a good tune is right around 45Hz.

What do you mean unloading is a bitch? Bottoming out the subs?

Yes, bottoming out=unloading. Losing the ability to mechanically control the sub is unloading.

If Fi is recommending 1.5-2.5 sealed(I'm not terribly familiar with the Neo motor Fi subs), you'll be fine with 2 cubes per. Be careful on the power you give them while it's just 2 subs in 6 cubes, unloading could potentially happen, especially if you're overpowering.

Tuning the ported side to the sealed resonance is a good practice. It also helps knowing the cabin resonant frequency. That would help determine WHAT to tune to and what resonance to make the sealed chamber. That way everything is working TOGETHER instead one of part of the build fighting the other.

[CleanSierra]

As far as port area, that's the tricky part. You really need to build for the 3 subs for port area instead of building for the 2 subs and being short when you add the 3rd.

[noser7]

Ok i see what your saying, would adding sound deadner and such change the cabin frequency? Im planning on running a soundstream xx 6500 at .2 hopefully i see 4000 out of it, it wont be on 16v.

For the port yes i understand, but i think i can make a panel i can change aeroports with?

[Triticum Agricolam]

1.5-2.5 cubes sealed sounds huge for a 12" sub. That sounds a lot like the specs for the ported side. Most 12" subs are going to want more like 1 cube each sealed.

You gotta be real careful with your sealed chamber size. Cone excursion goes up fast as your sealed side gets bigger. Like CleanSierra said, you will wreck your subs pretty fast if you don't get that chamber sized correctly.

This box is for a blow through right?

[noser7]

Yes its going in a ranger. Reason for the biiig box is cuz i have a big trunk snd id like to fill it up