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View Full Version : Questions about a ported box.



NE14MX
03-08-2005, 11:06 PM
This is the first box I have made but I have been given the dimensions from the speaker manufacturer. It is going to be 29 x 29 x 16 inches in height. Will contain two 12 " SE subs facing up. I was told to put 4 separate 4 inch ports in the back and place the 2 subs as far back as I can above the ports. A few questions.....

1. Does it matter how far apart i space the ports from each other and does it matter how close to the bottom they are?

2. I'm assuming they were talking about 4 inch round ports. Where can i buy these?

I want to do this right but kinda lost. Any help you guys could give will be appreciated

joeldirt
03-08-2005, 11:39 PM
This is the first box I have made but I have been given the dimensions from the speaker manufacturer. It is going to be 29 x 29 x 16 inches in height. Will contain two 12 " SE subs facing up. I was told to put 4 separate 4 inch ports in the back and place the 2 subs as far back as I can above the ports. A few questions.....

1. Does it matter how far apart i space the ports from each other and does it matter how close to the bottom they are?

2. I'm assuming they were talking about 4 inch round ports. Where can i buy these?

I want to do this right but kinda lost. Any help you guys could give will be appreciated


1.) Generally keep the ports the same distance or more that they are in diameter. YOu want to make sure the same amount of air is traveling in and out of the ports. if too close the air will be moving in and out of each port at different volumes and speeds, giving you an inacurate tuned frequency for what you are shooting for. YOu also want to make sure that they have enough space to achieve a good airflow. Too close to the bottom will cause a restriction to the natural movement of air, and cause a whistling, or added port noise.

2) you can get the 4" port at your local hardware store. PVC pipe is standard port material. you can round over the ends using a round over bit and router to further reduce unwanted port nosie. If you know any plumbers, or work near a construction site, you can come acrossed alot of PVC.

3) Did you account for bracing in your design? A solid ridgid construction is verry essential in the sound quality. Good luck.

NE14MX
03-09-2005, 12:06 AM
Thanks for the advice. As for bracing, I do not know if tey calculated that in or not. Those were the measurements given to me by RE. Did not mention anything about bracing so I am not sure and will call them back.


1.) Generally keep the ports the same distance or more that they are in diameter. YOu want to make sure the same amount of air is traveling in and out of the ports. if too close the air will be moving in and out of each port at different volumes and speeds, giving you an inacurate tuned frequency for what you are shooting for. YOu also want to make sure that they have enough space to achieve a good airflow. Too close to the bottom will cause a restriction to the natural movement of air, and cause a whistling, or added port noise.

2) you can get the 4" port at your local hardware store. PVC pipe is standard port material. you can round over the ends using a round over bit and router to further reduce unwanted port nosie. If you know any plumbers, or work near a construction site, you can come acrossed alot of PVC.

3) Did you account for bracing in your design? A solid ridgid construction is verry essential in the sound quality. Good luck.

joeldirt
03-09-2005, 02:22 AM
No problems, I drew out an idea for your box just doing some random brain storming. If oyu want PM me and I'll toss out a few ideas.