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DD9515's box building

 

Gold Member
Username: Johnfiac

IL Afghanistan,...

Post Number: 1083
Registered: Mar-06
Im ordering these subs at the end of the month and realized i might as well build a completely new box... what would everyone recommend for 2 9515's? And does anyone have the mathmatical formula for tuning ports?, and one more thing... i want to make my box cover the wheel wells that stick up on the inside of the rear with the box, its about 36' between the 2 and once you are above the well, its about 45' so i want to sorta have my box get bigger at the top.. has anyone did this before, does it mess with the sounds being shaped like that? here is a ghetto example... btw the port is also going to be at the bottom of the box in the space between the wheel wells, so the subs will actually sit more in the area where the box is bigger....

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Gold Member
Username: Johnfiac

IL Afghanistan,...

Post Number: 1095
Registered: Mar-06
Keep this bumped until its answered.... subs will be here no later then the middle of next month hopfully... i want to atleast get the box built so i can find area for my 4 HC2400's i will be adding in the next month along with the next PHD5000d amp..
 

Gold Member
Username: Johnfiac

IL Afghanistan,...

Post Number: 1123
Registered: Mar-06
^bump people!!!!!!!!!!!!!!!!!!!! grrrrrrrr.... and another thing... has anyone tried tube ports that come out then bend, or with the subs and port facing up? Im debating on when i build this box, i can build it to fit in the rear and fire the port towards rear, but the box will be smaller, or i can use the complete rear and fire the port upwards, otherwise i have to start sacrificing my back seats... already have to sacrifice one for a place for the batterys to sit.... But if they were to fire upward...if i stuck some ports in there that are bend on a 90degree angle so they are facing forward... woould it be louder? ...



And i need that mathmatical formula for ports!!!! NOT only the round ones...that you can find on the12volt.com, i prefer to make the port more square\rectangle so i can make replacable ports to this basic design i got from marshall.
 

Bronze Member
Username: Djl

Post Number: 26
Registered: Sep-06
The DD9500 likes around 4-5 cubes net per sub. Ideal box would be 9 cubes net for the pair tuned to 40Hz for best combo of spl and sq. Tune at 45Hz for spl and 36Hz for best sq.
Port opening area is 16sq" per net cubic foot of interior box volume. For 40Hz tuning make the port 16" long. For 45Hz make the port 13" long. For 36Hz make the port 20" long. The port opening area will be the same for each tuning. Forget about using a box program for the subs. This tuning formula is based on IN CAR tuning.
 

Bronze Member
Username: Djl

Post Number: 27
Registered: Sep-06
If you need further information on tuning or boxes for DD subs you can e-mail my son, Jassa, the owner and designer for DD, at sales@ddaudio.com. You can also talk to Steve at 405-239-2800 for box design help.
 

Gold Member
Username: Johnfiac

IL Afghanistan,...

Post Number: 1134
Registered: Mar-06
DJ your one lucky guy if your son owns it... tell him to hook it up! ill give them a call or email
Thanks!
 

Gold Member
Username: Southernrebel

Monroe, Louisiana DD 9515d~~]...

Post Number: 4213
Registered: Mar-04
Killa,

A port is a port. You look at port area and box volume when determining port length.

ex:

A 4" round port would be the same length as a 3.5445"x3.5445" square port (given the same net box volume and tuning)

Both will give you 12.56sq inches of port.

BUT, w/ interchangeable ports...you have to calculate the displacment of the wood used to build the port and factor that into your total displacment.



EX1: 2cuft gross box w/ 1 4" round port tuned to 35hz (.15cuft sub displacement)

The port would need to be 12.74" long, net volume would be 1.757cuft.



EX2: A 3.545"x3.545" interchangeable port (5.045"x5.045" external dimensions) in the same 2cuft gross box (w/ .15cuft sub displacment) tuned to 35hz agains

The port would need to be ~13.75" long and would give you 1.65cuft net.

The displacment of the wood the port is made of would be ~.11cuft.
 

Gold Member
Username: Southernrebel

Monroe, Louisiana DD 9515d~~]...

Post Number: 4214
Registered: Mar-04
Killa...

DJ runs Audioque :-)
 

Gold Member
Username: Johnfiac

IL Afghanistan,...

Post Number: 1135
Registered: Mar-06
haha forreal? i only been on audio forums for around a year im just learning this stuff.... need to become cool with some of them so they can sponser me down the road when im hitting the 180's
lol
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