Question about enclosure and port

[jarod027]

That rule is mostly for slot ports, aeroport are more efficient, a round port needs about 9-13 SQ of port per cubic feet, said that, that´s why i would use minimun 3 4" ports, besides that, where do you get 56 SQ of port with a single 4" tube?????

pi x ®2

3.1416 x (2)2

3.1416 x 4 = 12.57 square inches!!

3 4" ports would be 37 square inches

Simple basic maths...

because the tube is 4.5" long as well.

[bkolfo4]

because the tube is 4.5" long as well.

Which would be volume, not area. . . we are looking at sq-in, not cu-in.

[jarod027]

Which would be volume, not area. . . we are looking at sq-in, not cu-in.

Oh, alright I understand. confusion on my part. So, if i'm going with that many ports, how do I get a frequency as low as 30?

[fecupe2001]

Actually my friend, it does not. . .but it is a nice approximation for those that cannot figure out how much port area they really need. . .

As i said before, for people that not care on competing or looking for the maximun efficiency on a box, port area depends on a lot of factors including power, but once again, for people that don´t know and don´t care really, port area depends mostly on the box size and power...

[jarod027]

So, for a box this size, do you guys recommend doing slotted ports rather than round?

[vee333gp]

fecupe i agree port area works with power and volume so what power u using to drive woofers

[jarod027]

fecupe i agree port area works with power and volume so what power u using to drive woofers

audioque1200d

[fecupe2001]

So, for a box this size, do you guys recommend doing slotted ports rather than round?

Well, they both are nice, since you are not looking for score and you don´t care about testing wich one works best on your car, AERO FTW!! They take less internal space, easier to retune and test, you can use cheap PVC tubes and they need less area most of the time.

fecupe i agree port area works with power and volume so what power u using to drive woofers

Well, generally, the more power you have the more port you can get, this also depends on the car, my little swift HATES big ports and big subs, works great with 10´s and 12´s , bigger than that, scores the same or maybe less. My explorer likes much bigger port, said that:

i have 16 SQ of port per cubic feet on the swift and worked awesome with my 6K amplifier, it broke down so now i have a 2K amplifier and still sounds loud, but i know it could be a lot louder with a smaller port, i don´t have the power for that port.

The explorer has 20 SQ per cubic feet because i´m gonna use a 8K amplifier wich i haven´t bought yet, but with barely 3K watts it´s hitting around 151 right now, i´m just dreaming on a high 52 with my new amp, we´ll see...

[jarod027]

So how many square inches of port do i need for aero?

[bkolfo4]

but once again, for people that don´t know and don´t care really, port area depends mostly on the box size and power...

But that is not correct. . .It does not depend on box size at all. Those are just approximations so people are not constantly asking how much port area they need, since the true mount of port area required for a port to operate correctly without compression is almost never achieved in a vehicle.

If I have a BTL 18 on 4000 watts tuned to 35 Hz in 6 cuft vs 10 cuft, I do not need a different size port.

If I have a BTL 18 on 2000 watts vs 4000 watts in the same 10 cuft, they do not require the same amount of port area.

Port size is correctly determined by cone displacement and tuning frequency. . .