AB XFL 12's Box Build...Missing some info...

[FadedSpy 10+ year member]

I'm building a box for 2 XFL 12's I've decided to do 5 cubes @ 35hz but the recommendation is 15-16 square inches per cube so I need between 75-80 square inches of port. That seems like a lot and I can't quite get it figured out!

My box dimensions will be 38" Wide x 14" Tall x 24" Deep and I'll be using 6" PVC for the ports. No matter what numbers I plug into torres I can't seem to get to the 75-80 square inches of port per cube using 6" PVC. Any suggestions?

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[mylows10 5,000+ posts]

Box is to big. 4^3 at 33 hertz is perfect. But with that box size. 10.5 inches long gets you at 32 hertz

 

[FadedSpy 10+ year member]

You sure it's too big ? I've got guys all over the place telling me that they need to be in 5 cubes @ 35hz ...I'm still using that first box I made which as 4^@34hz and they sound pretty good. I was just seeing what a 5 cubes with Aero Ports might do?

 

[FadedSpy 10+ year member]

I read this quote from an AB dealer on another forum today as I was Google happy

"for the box shoot for 4.8-5 cubes tuned to 32-33hz with 15-16 sq in of port per cube"

 

[mylows10 5,000+ posts]

You'll prolly be fine with that box. But what I've seen and done the 4^3 shared does the trick pretty well

 

[mlstrass 5,000+ posts]

6" PVC is 28^2 of port, you'd need 3 of those to do 75-80^2....

 

[Jeffdachef 5,000+ posts]

I'm building a box for 2 XFL 12's I've decided to do 5 cubes @ 35hz but the recommendation is 15-16 square inches per cube so I need between 75-80 square inches of port. That seems like a lot and I can't quite get it figured out!
My box dimensions will be 38" Wide x 14" Tall x 24" Deep and I'll be using 6" PVC for the ports. No matter what numbers I plug into torres I can't seem to get to the 75-80 square inches of port per cube using 6" PVC. Any suggestions?

Aeros are a little more efficient then slot ported so you dont need 15-16 inches of port per cube, especially if you do a proper flare with your aero. Try a 8 or 10 inch aero instead. If you go 10, and cant find pvc pipes, you can do it with sonotubes and fiberglass the flares. You can also do an octoport if you have the woodworking skills.

Careful with the power settings afterwards, you can easily bottom out with a much more efficient design with that much airspace and port area along with overpowering it.

 

[FadedSpy 10+ year member]

Aeros are a little more efficient then slot ported so you dont need 15-16 inches of port per cube, especially if you do a proper flare with your aero. Try a 8 or 10 inch aero instead. If you go 10, and cant find pvc pipes, you can do it with sonotubes and fiberglass the flares. You can also do an octoport if you have the woodworking skills.
Careful with the power settings afterwards, you can easily bottom out with a much more efficient design with that much airspace and port area along with overpowering it.

Thanks Jeff...If I used TWO 6" PVC ports and used the hot ceramic bowl trick to flare the ends and say they are 18" long each (Because that's what Torres tells me they should be to achieve 35hz) Should that be sufficient enough port space for 2 of these subs you think?

 

[FadedSpy 10+ year member]

Box is to big. 4^3 at 33 hertz is perfect. But with that box size. 10.5 inches long gets you at 32 hertz

You know anybody who's built a box for 2 of these and used Aero Ports or a Sonotube instead of a Slot Port?

If I decrease the depth to 20" It'll put me a 4.5^ft after woofer displacement but I could drop it to 18" deep and be right at 4^ft after displacement. I'm just curious as to the affect an aeroport might sound vs the slot port they're in now. The slot port box I built (The one you gave me the dimensions for) sounds awesome, I'm just trying to get as much out of them as possible.

What do you think? Any experience with it?

 

[mylows10 5,000+ posts]

The box I told you to build is actually 5^2 with port so you would need to make the box smaller A 6" port at 16" long should do pretty well especially on the lows if you want louder then usually you'll need to tune higher. Best thing to do is find the resonance frequency of your car. Build your box to peak there

 

[FadedSpy 10+ year member]

The box I told you to build is actually 5^2 with port so you would need to make the box smaller A 6" port at 16" long should do pretty well especially on the lows if you want louder then usually you'll need to tune higher. Best thing to do is find the resonance frequency of your car. Build your box to peak there

This is the box I built, it's 5.73^ft gross & 4^ft Net (My Port Length was Only 23.5" to tune it to 34hz) with 57 sq in of port area.

So, how in the world do I find the resonant frequency of my Intrepid? Is the box I have considered 4^ft since that's the Net or is it considered a 5.7^ft box?

 

[mylows10 5,000+ posts]

Sealed box. Meter on termlab peak frequency is what you wantb

 

[Jeffdachef 5,000+ posts]

This is the box I built, it's 5.73^ft gross & 4^ft Net (My Port Length was Only 23.5" to tune it to 34hz) with 57 sq in of port area.

just play a sweep tone on a woofer on a sealed box and see which frequency makes your car rattle apart the most if you dont have a term lab.

You might want to do your sound deadening before doing this though as it will lower it by a few hertz once you are done.

 

[FadedSpy 10+ year member]

just play a sweep tone on a woofer on a sealed box and see which frequency makes your car rattle apart the most if you dont have a term lab.
You might want to do your sound deadening before doing this though as it will lower it by a few hertz once you are done.

Well, I'm 1/2 way there...They're sitting in a 2.75^ft Sealed Box at the moment. I Downloaded some SPL Test Tones which has 20Hz - 100Hz. I just need to listen to them all to see at what level my car really hits hard? Then that's the Hz level I want to tune my next ported box to?

 

[Jeffdachef 5,000+ posts]

Well, I'm 1/2 way there...They're sitting in a 2.75^ft Sealed Box at the moment. I Downloaded some SPL Test Tones which has 20Hz - 100Hz. I just need to listen to them all to see at what level my car really hits hard? Then that's the Hz level I want to tune my next ported box to?

not necessarily the hardest, just the one that violently rattles. Sometimes a hard 45hz drop feels louder but its not the peak car frequency.