Ported box help

[96civ 10+ year member]

OK I used the AJDesigner software to determine the information I need in order to build a ported box, but I have a few questions about the outputted information.

OK I put in my T/S parameters for the Kicker 0512L704 I have and the information that was outputted was:

Vb = 3.655 ft^3 // ok I understand this, volume not including displacement of the sub or port

Fb = 32.2Hz // tuning frequency of the box I'm assuming

F3 = 27.3442Hz // roll-off frequency of the system

but here's where I get confused....

Lp = 5.76385 in. // I want a slotted port box, and this is the length of the port, but how do I determine the L shape dimensions for the port?

Port volume = 70.1674in^3 // meaning that is the l*w*h of the port, but how do I incorporate this into the box?

...............

Where is a good link I could go to in order to manually build a system because I cannot choose a specific tuning frequency using this software, and I would like the freedom to do so.

Click to read more...

 

[docutech 10+ year member]

Have you checked this site?

http://www.accelerator-pedal.com/ported-box.asp

This link was reccomended by Mustangowner.

 

[96civ 10+ year member]

Have you checked this site?http://www.accelerator-pedal.com/ported-box.asp

This link was reccomended by Mustangowner.

That's a **** cool site, but I have one question.

How do I obtain the flattest bass response for a ported box? Find the volume for a sealed box that provides the flattest bass response (qtc = .707), or do I have to use a different set of equations?

 

[docutech 10+ year member]

I dont believe that is an option with a ported box. A sealed enclosure will give you a flat response...

Custom nclosure gurus may have to help us out on this one...//content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

 

[Jordantyler 10+ year member]

i agree i love that site!

 

[flakko 5,000+ posts]

I dont believe that is an option with a ported box. A sealed enclosure will give you a flat response...
Custom nclosure gurus may have to help us out on this one...//content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

i aint no guru, but i tink i can answer that hehe, you CAN get a flat response out of a ported box, just not as flat as a sealed.

just tune it lower, 28 ish. go too low and you get boomy.

 

[96civ 10+ year member]

OK so it is the tuning frequency that ultimately determines how flat the curve is in the bass range, right?

 

[flakko 5,000+ posts]

OK so it is the tuning frequency that ultimately determines how flat the curve is in the bass range, right?

cha, pretty much. see if you tune it to 32 hz, youll see a GIANT hump in that certain area of the freq range. lets say you tune it to 28 (which is tougher to hear than 30-35), the hump will be on the 28 hz area and boost that range while the rest 28 and up will be i guess pretty much flat?

and the tuning to 28 will also boost the tougher to hear freq's. so its a per say

 

[96civ 10+ year member]

OK I've manually setup a system, but I'm not sure if it's right. Also I don't know how to construct the port pieces.

In the Kicker manual the street bass setup for my driver is: 2.5ft^3 + port displacement; 2.5" x 13.25" port

Port length:

Av = 33.125in^2

Vb = 2.5ft^3

Fb = 31Hz

Lv = (Av * 1.84x10^8)/(Vb*1728*(Fb/.159)^2) - .823sqrt(Av)

Lv = 32.379" and I've estimated it to 32.375" for easy cutting

_________________________________________________________________

Displacement of the port:

Dp = ((W+T)*H*D)/1728

W = 2.5

H = 13.25

D = 31(5/8)"

T = .75"

Dp = .788ft^3

_________________________________________________________________

Driver displacement = 0.078ft^3 = Ddp

Thus

Vb + Dp + Ddp = Net volume

2.5 + .788 + .078 = 3.366ft^3

_________________________________________________________________

Box construction:

3.366 * 1728 = 5816.448

Internal:

W = 23.5"

H = 13.25"

D = 18.6875 (estimated for cutting purposes)

External:

W = 25"

H = 14.75"

D = 20.1875"

Tuning frequency: 31Hz

Port width: 2.5"

Port area: 33.125in^2

Port length: 32.375"

What I need to know are the dimensions of the pieces the make up the port.... or for lack of better words, the two pieces that make up the L shape.