Tuning a box

[holykaos 2]

So made a design for 4 Sundown audio sa-8 Dual4. I need to figure out the port tuning for the box. Here's a work up of it i made.

Its all 3/4 mdf with a double top plate to flush mount the subs.

Box size is 39w 12d 16h(16 3/4 with top plate) The port size i was thinking was 6h 8w 7 1/4d

[pro-rabbit 64]

So you have around 3.3ft3 gross right?

What is your goal to have for net ft3?

What is the goal of the enclosure?

[ricksi30 923]

That is tuned really high probably ~60 if I'm reading it correctly.

[pro-rabbit 64]

Yea, I didn't even do the math on it as you can tell that it will be very high. Also, depending on what the goal is, that is a generous amount of port area.

[ricksi30 923]

Yea, I didn't even do the math on it as you can tell that it will be very high. Also, depending on what the goal is, that is a generous amount of port area.

Agreed.

[holykaos 2]

The box is the size it will be around 3.5ft3 and after bracing and such around 3.2-3.0. I know i want to do a square port and i want it to hit as low as i can with 4 8's(trying to break stuff in my car).

[pro-rabbit 64]

Can you increase the enclosure size? I would shoot for 3 - 3.3 net not gross.

Edited January 25, 2012 by pro-rabbit

[holykaos 2]

I can Bring the depth out about 2 more inches. Can't go higher or wider.

[pro-rabbit 64]

What kind of application?

[holykaos 2]

Like i said i want it to be loud and low. I want to see what i can break in my car. Its going into a hatchback look up my old build log

[holykaos 2]

So does any one have any idea on port area for this box and what it would need to be to tune it. The box is maxed out at 39 wide but it can be about 18 deep and 17 high. I am good at building and tuning slot port boxes but i have never done a square port box.

[95Honda 486]

Port area is based on power and driver displacement. You need to model to figure this out. It has nothing to do with enclosure volume.

Any other method to calculate is BS...

[holykaos 2]

All the calculators i use have always done me right but its always been for slot ports never a center square port. 90% of the box's i have built were all simple box's never done any of the huge multi sub box's. But i would still like to find out what my port size would need to be for 4 Sa8 dual 4s on 2 hifonic's 1200.1(1 am per 2 subs).

[chrisbarr90 0]

i asked a similar question in the sa8v2 presale thread. jacob replied with 0.5 cubes to 0.75 cubes each depending on your power -- tuned low... 30-35 HZ

Area per woofer of 12 in^2 for port area

Edited January 31, 2012 by TILLitHERTZ

[holykaos 2]

Ok so like always i can't make up my mind. I wanted the 4 in a row Top mounted box with the front facing center square port. But the box size would not look right with a small port.

So in good old fashion i changed my mind and made a new build. Just looking for a little input on the box and if my math is right.

The box is 22"deep 40"wide 19"high Its all 3/4 mdf (besides the cross in-between the subs that's 1/2 and acting as bracing) The port is 5"wide and 17.5"high and should be around 61.25" long if i did that right.

Here's the box and what it should look like. This is a bottom view so you can see the sub cut-outs and such.

This is what i used to tune and all that good stuff.