So i was thinking of 2 15's fi bl but it seems i will not be able to build the proper box. Don't want to spend money on good subs just for the box to be crap. So i was thinking of 12's. What do i suffer from by getting 2 12's?

Cone area, nothing else

Why have more or less cone area?

The 12's have less cone area, which means lower potential output capabilities. But it's a better trade-off than having 15's stuffed in an enclosure that's too small.

what will be an outcome if the box is to large for the 12's?

I drive a 2007 escape i have max dimensions of LxWxH 20x41x22

what will be an outcome if the box is to large for the 12's?

I drive a 2007 escape i have max dimensions of LxWxH 20x41x22

Why would you build it too big?

you would use less power.

Output.

BEEFCAKE!

Not wanting to build it to big just wondering. I am very new to car audio, only thing i been lookin at was smd forum but now looking around at others. So output you are referring to the different frequency levels? Like the music would sound better at certain frequencies and not get anything from others?

Not wanting to build it to big just wondering. I am very new to car audio, only thing i been lookin at was smd forum but now looking around at others. So output you are referring to the different frequency levels? Like the music would sound better at certain frequencies and not get anything from others?

No they will both sound the same. In an ideal enclosure the 15's would be louder.

Alright so using this formula on the bottom given to me from someone here i need 67.35in^2 and if i build a box thats is 5cuft net i have a port area of 92.50in^2 and tuned to 32hz is this a good way to go?

dv = 39.37 (fb x Vd)^1/2

dv= minimum port diameter of vent in inches

fb= box tuninf frequency in hertz

vd= cone displacement in cubic meters (one way xmax in meters times cone area in meters)

just noticed your in san Antonio, im in san marcos

Alright so using this formula on the bottom given to me from someone here i need 67.35in^2 and if i build a box thats is 5cuft net i have a port area of 92.50in^2 and tuned to 32hz is this a good way to go?

dv = 39.37 (fb x Vd)^1/2

dv= minimum port diameter of vent in inches

fb= box tuninf frequency in hertz

vd= cone displacement in cubic meters (one way xmax in meters times cone area in meters)

No need to have that much port area with a 32hz tuning. The port would take up a ton of room too.

Box for 2 FI BL 12's. Looking for tune at 32hz. What i get is 5cuft and port area of 92.50in^2. Bracing and displacement is .61cuft

Length 20

Width 40

Height 20

Port

Length 38

Width 5

Height 18.5

your port is huge. i would take it down to around 50-60in^2, there is no need for that much port area plus it takes up alot more space in your enclosure.

Alright let me calculate this again. It will take me a little while. I will try a smaller box and figure new port.

your port is huge. i would take it down to around 50-60in^2, there is no need for that much port area plus it takes up alot more space in your enclosure.

Of course you don't need that much port. And Small didn't have a clue what he was doing when he created the formula.

If his formula is so ludacris why even model a sub for an enclosure using specs. You know those T/S parameters as in thiele SMALL. If he didn't have a clue when it came to port compression how is it he was capable of creating formulas for a transducer.

That formula is for port COMPRESSION not port noise. There is a huge difference. You may be willing to lose 1-2 db by "saving space" by using a smaller port. But by then it would have been the same as doing the smaller subs.

Alright changed it up a bit. Still with the same displacement for subs and bracing at .61cuft. Got my tuning at 32 with 4.94cuft net and port area at 70.13in^2

Length 20

Width 40

Height 18

Port

Length 28

Width 4.25

Height 16.5