Fi Q 12 ported enclosure question

[RetchedOne 0]

Waiting till thursday to order teh new 12" Q but I want to get started on the box...

I've got room for a 29.5x19x8.75 deep box... (this is going in the back of a 350z)

This puts it at about 2.05 sq ft after the driver displacement.

I was going to go sealed, but have changed to ported...

I need to figure out the length of the ROUND port to use...

I saw a post on the 350z forum where a guy used two 3" ports at about 32Hz

"needed 34" total of 3" port to be tuned @32Hz" Can someone confirm, using your awesome math skills, that 34 inches total of 3" port is correct?

I'll need to split the ports into two ports...

I'm aiming for this look...

FI Q12 in the Z... - MY350Z.COM Forums

Using these ports

Box will be sunken into teh spare tire area, and sealed on teh bottom with fiberglass, and "dynomat"

Box dimensions

none of these are my pics, or idea, I "borrowed them" So props to the original poster.

[RetchedOne 0]

Port part list -

www.partsexpress.com

(2) 268-320 Outside Flares

(2) 268-324 Elbows

(2) 268-326 Couplers

(2) 268-328 Straight Tubes

(2) 268-322 Inside Flares

[BKOLFO4 29]

I think your calculations for volume are off, unless I missed something.

28 x 7.25 x 17.5 = 2.05 cuft gross, and that is before driver displacement, not after.

The picture says 2.25, which is not correct, even if those are internal dimensions.

If the Q is .16, you have 1.89 cuft after driver displacement.

If you have 1.89 cuft before port displacement, you can use (2) 3" ports that are 20.75" long (measured through the center, since you will have an elbow).

That makes the port displacement ~.2 cuft and net volume ~1.7 cuft.

1.7 cuft tuned to 32 Hz with (2) 3" ports x 20.75" long.

Brian

[RetchedOne 0]

I think your calculations for volume are off, unless I missed something.

28 x 7.25 x 17.5 = 2.05 cuft gross, and that is before driver displacement, not after.

The picture says 2.25, which is not correct, even if those are internal dimensions.

If the Q is .16, you have 1.89 cuft after driver displacement.

If you have 1.89 cuft before port displacement, you can use (2) 3" ports that are 20.75" long (measured through the center, since you will have an elbow).

That makes the port displacement ~.2 cuft and net volume ~1.7 cuft.

1.7 cuft tuned to 32 Hz with (2) 3" ports x 20.75" long.

Brian

I actually didnt do the math... I took the poster's word...

Should the box by made slightly larger?

[RetchedOne 0]

Based on this -

Q 12 – We recommend using a sealed box in the neighborhood of .8-1.5 cubic feet of volume (after all displacements for those wondering). (I personally think that 1.2-1.3 cubic feet is optimal imo)

Ported box we recommend using 1.8-2.5 cubic feet @ 28-33Hz (I personally think that a 32hz tuning is optimal, and has the most output and is still the most musical daily driving). Use 12-16 square inches of vent area per cubic foot of volume

I need to get the box up from the 1.7 to closer to 2 cuft...

If I take the box to 28 x 8.5 x 17.5 = 2.4 minus the driver = 2.2 cuft maybe i woudl do slightly less (Internal dimensions)

So do i need 2- 3" ports at 24 inches each?

How do i calculate the port length?

Also -

I spoke with Scott on Monday (I think it was Scott)

He recommended I not bother adding cooling but suggested High QTS,

- Do i still want High QTS, being ported?

- Do I need other options, such as cooling?

I plan on running a Single Alpine M-1000 (1000 watts RMS into 2 Ohms)

Also - Do i want the dual 2 Ohm or Dual 1 Ohm?

the Amp can run at 2 Ohms, Mono channel Amp Alpine MRP-M1000

[RetchedOne 0]

Just ordered the new Q!!!

Totally stoked!

[mr.tigger 1]

Box dimensions

none of these are my pics, or idea, I "borrowed them" So props to the original poster.

when i try to put those measurement in a calculator i got 2.055 is this calculator worng??http://www.the12volt.com/caraudio/boxcalcs.asp#rec

Edited April 2, 2010 by mr.tigger

[RetchedOne 0]

He subtracted the MDF thickness.

I'm aiming for about 2.2 cuft, minus the ports...

The picture of the box was just for reference