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Omarvelous
01-18-2004, 05:30 PM
I was wondering if you could use 2 ports, both half the length if u had used 1 port.

Not suree if that was clear enough.

For example, say for 1 4" diameter port, the length has to be 16"

Could I have 2 4" diamter ports that are both 8" in length and get the same frequency?

And is it better to have a bigger or smaller diameter?

helotaxi
01-18-2004, 05:59 PM
Actually it works quite the opposite. As you increase the surface area of the port you must increase its length to keep the same tuning. If you are adding a second port of the same size the length will be close to (but not quite) double the length of a single. Keep in mind that these ports will now displace 4 times as much air as the original single port inside the box thus making the box smaller and requiring an even longer port to keep the same tuning freq. Box size is just as important as tuning freq in sub performance so to get the sub to really work correctly, you are going to need a whole new box.

Omarvelous
01-18-2004, 06:31 PM
So like say a 4" Diameter requires 15" length, and a 2" Diameter only requires like a 3" , would you suggest going for the 2" diameter?

helotaxi
01-18-2004, 07:38 PM
So like say a 4" Diameter requires 15" length, and a 2" Diameter only requires like a 3" , would you suggest going for the 2" diameter?

You want a large port for the box to sound good. Once the port starts getting too small in diameter you run into port turbulence. The sub is still moving and the air is still trying to move in and out of the box through the port but now you are trying to move the same volume of air through a smaller opening. For that to work the air has to move faster, and it starts to swirl and buffet. This buffeting is audible.