$5 to the first to people to help me with my port length

[WOT]

Just transferred $10 from my visa to paypal for someone to answer this question. I need someone to give me a port depth, and then hopefully someone to verify, I'll give $5 to both of ya if you agree. Spend it wisely lol

I REALLY need help figuring out how to tune this port to 40hz, i just need to know the depth to make it. The last thread I made I got VARIOUS numbers, via pm and such from people, varying from 7.5" all the way to 21.6" depth to get my tune.

Ive also heard I had 210" of port - 245" of port. So I dont really wanna build the box until IM SURE, cause Im building the box in the car, so I wont have any second chances here really. And since Ive already built everyhting in the car, except the front baffle and port. Im jammed here

Heres the specs, hoping there legible, the square in the port is what I think is throwing everyone off, its a 15.5" span across the port on the INSIDE of the port, if you were to draw a square INSIDE the port, it would have 11" sides, and its 6" wide, it is 30.5" tall inside.

The pic i made is a bit decieving to, its 37.5" wide OUTSIDE, and 32" tall OUTSIDE

Gumby and supernova were the only ones who showed me there math really, heres what they told me

"you have 225.60cu in of port area, and assuming that the walls of the port are 0.75" MDF, there is a total displacement area of 277cu in.

In order for the box to be tuned to 40hz, with a max internal volume of 15.6cu ft"

"I'm figuring 245 sq.in. port area from the pic. If your pic is representative, your port length can be anywhere between the thickness of the MDF to 5" with 15.5 cubes after port"

No offence to the guys that helped me so far, as this math is way over my head, as I only have experience with slot ports and aeros, and this shape is killing me.I just really need to be sure, as I put a decent ammount of time into this so far, and fiberglassing is gonne be a pita to, and if its tuned to some random freq and I have to tear it out I wouldnt be happy lol. I would like to thank drpeeb and gumby for there help so far though, cool guys

Click to read more...

 

[mazzasec 5,000+ posts]

Ill do it for $50 dollars

 

[fasfocus00 5,000+ posts]

what the hell is the reason for the extra width? you just making things difficult

 

[fasfocus00 5,000+ posts]

i say around 14"

 

[defianttek 10+ year member]

You have 225.25 square inches of port, working on the other math now

14" sounds about right

 

[DonH 5,000+ posts]

why the hell do you have the port look like that is my question.

 

[KyleBechtold 5,000+ posts]

why the hell do you have the port look like that is my question.

for more port area than his previous box

 

[fasfocus00 5,000+ posts]

You have 225.25 square inches of port, working on the other math now
14" sounds about right

where's our money, you can pm me and i'll give you my paypal addy.

 

[WOT]

what the hell is the reason for the extra width? you just making things difficult

Increases port area quite a bit. Im trying to get as much port area as possible on a 32 X 37.5" front baffle, while still squeezing 4 15'f on that baffle, so I can continue with my wall

I also am not just gonna pay ya for a guess of 14" lol, 225 seems to be the common concensus for port area, but Im getting such variation on length, that its driving me nuts

 

[ShiningBuick 10+ year member]

I got 10.19"

 

[WOT]

Thanks, but as i mentionned, why is everyone getting different numbers

 

[ngsm13 5,000+ posts]

Your port area is 230 square inches.

You GROSS internal volume before any displacements is: ~15.75 cubes

-Your subwoofer displacement assuming .19 per subwoofer: .76cubes

-With 230 in^2 of port, 19" long, including wood displacement, your port displaces 2.72 cubes.

-Assuming a 40hz tuning and 230 in^2 of port, with a NET volume after ALL displacements of 12.25, your port length will be 19" for 40hz tuning.

Total Volume: ~15.75 cubes internal

Total displacements: (2.72 + .76) = ~3.5 cubes

Your final NET internal volume is 12.25cubes, with ~230 in^2 of port, with a port length of 19" and final tuning of ~40hz

kthnxbi.

nG

 

[Xprime4 10+ year member]

Your port area is 230 square inches.
You GROSS internal volume before any displacements is: ~15.75 cubes

-Your subwoofer displacement assuming .19 per subwoofer: .76cubes

-With 230 in^2 of port, 19" long, including wood displacement, your port displaces 2.72 cubes.

-Assuming a 40hz tuning and 230 in^2 of port, with a NET volume after ALL displacements of 12.25, your port length will be 19" for 40hz tuning.

Total Volume: ~15.75 cubes internal

Total displacements: (2.72 + .76) = ~3.5 cubes

Your final NET internal volume is 12.25cubes, with ~230 in^2 of port, with a port length of 19" and final tuning of ~40hz

kthnxbi.

nG

ding ding ding we have a winner //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

Honestly, i'll paid him just for the effort.. you don't want to tune a little lower? I though your new box was more about sq

 

[WOT]

But you see what I mean about every single person giving me a different answer?

Appreciate the effort NGSM13, I believe gumby said 21" so you guys are ballparking it together, but Ive also had 2 people tell me 14" and 3 tell me 10.25"

I may just end up having to double baffle the box if i need 19" port depth, as I have that angle in the back of the box after 18.25

 

[WOT]

And I seriously am going to paypal whoever throws me some correct numbers, no problem with that, as this is holding me up large