can’t figure out port

Ok this may be a newb question but say I want to have 2 ports in one chamber of a box. If I use 2 inch ports would that count as 1 4 inch port or still just a 2 inch port but add the lengths of each port. Sorry if this is simple but I'm stuck.

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-ETS-
Escape The Scilence

Two 2" inch ports would be like having one 4" port. It will increase you port area.

FYI, if using the port calculator on the site. Make sure you are using NET volume to figure tune. Take outside dimensions to figure your GROSS. Then subtract port volume, driver displacement and bracing to find your NET airspace.

If you need help to get the right goal of tune and volume. Just hit me up. I can walk you through it in more detail if you need it.



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It will take (4) 2 inch ports to equal (1) 4 inch port.   Formula for area of a circle is Pie X (Radius squared)  2 inch circle = 1 x 1 x 3,14159 = 3.14159    4 inch circle = 2 x 2 x 3.14159  = 12,56

i am an idiot wrote:

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It will take (4) 2 inch ports to equal (1) 4 inch port.   Formula for area of a circle is Pie X (Radius squared)  2 inch circle = 1 x 1 x 3,14159 = 3.14159    4 inch circle = 2 x 2 x 3.14159  = 12,56

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Good catch "i am". That is indeed correct. Two 2" ports would be closer to a 3" port.

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i am an idiot wrote:

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No catch i was typing when you posted.  I had no idea you had posted.

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In that case you should have just played it off as you had I would have lol

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ok thanks guys. I dont need it to be dead on balls accurate as this will be my daily driver box not competition. Ill calculate it as a 3 inch port. Then all i need to do is buy the DC LVL4 XL to go in it and ill be a very happy man. :)

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-ETS-
Escape The Scilence

You will want more port area then that for a DC lvl 4 XL. You will want to build a slot port box. What size sub is it going to be?

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Ok Well I was originally going to go with a 12 but now im leaning toward the 15. Below is a sketchup rendering of the box tuned to 35Hz. The overall size is 38W x 10H x 20D Which gave me a net volume of about 3 FT^3. The Port is 6.25W x 8.5H giving me enough port area given 16 IN^2 per 1 cubic foot. The front is cutout so you can see the port inside.




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-ETS-
Escape The Scilence

Its late now So i cant call, but i would send DC an email asking there recommendation for port area per cubic foot. That port area seems to be too small to me.

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Still too small? lol damn thats a fat port though.If I make the port any larger the port will have to be longer and its already really close to the sub. This whole shallow design is essential in my car due to its the best design for being loud as a daily driver. plus the trunk opening is extremely difficult.

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-ETS-
Escape The Scilence

I didn't pay attention when you said your port was 16sq.in per cubic foot. I thought you meant 16sq.in total and i didn't do the math on it. I just figured it and its actually 17.7sq.in. per cubic foot. 6.25 X 8.5= 53.125 / 3= 17.7sq.in per your 3cu.ft. net. That should actually be pretty close and maybe even a bit bigger than needed. Sorry i mis read it before and didnt take the time to figure it. I would still contact DC to see what they recommend. It would be easier to mod the enclosure in the sketch up phase then it is when you get it together and it doesn't sound right. I know you don't intend to compete with it, but the more perfect it is. You will see higher output and better sound as well.

If they actually recommend a bit less then you have figured now. You port can actually be shortened a bit to keep the tune you have selected.

Again very sorry i didn't take the time to read your post more thorough and do the math on it before I posted, but i do stand by contacting DC for there recommended port area. They spend lots of time to figure out what is going to make there driver preform to there max.

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Its good man dont worry about it. Box design isnt my strong point so for all i know you could have been right since ive never dealt with a high performance driver like the DC before. Thanks a lot for your input. Other than that what do you think of that box design? Do you think ill need to double the baffle board to prevent flex or will the port provide enought support? I could get away with small internal bracing too.

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-ETS-
Escape The Scilence

If it was me i would double baffle it. That sub is not light at all and has a very strong motor. That enclosure will need to be very strong adding bracing is something i would for sure do aswell.

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Ok ill either double baffle or just get the baffle a solid 1.5" thick. Add some internal bracing and do all the math again. Thanks again for your input man.

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-ETS-
Escape The Scilence