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Hugh G. Rection

understanding ports, a lesson in dimensions vs efficiency.

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as we all know, there is always the debate over how to get your enclosures to be as efficient as possible. there so many factors that go into this, but i am only going to explore one of them with this little write up. the port itself, is such a critical element of an enclosure, as we all already know.

you can help yourself immensely in this area with a basic understanding of aerodynamics and simple physics. so with that out of the way, here we go.

we have all seen it time and time again, you can have 2 boxes that seem identical on paper. same internal volume, same subs, same power, same tuning, heck even the same amount of port area, yet different results.

a circular port is a very efficient design, and its not only because you can attach a flared mouth to the end of it. this is because it uses the least amount of actual material on the inside as possible.

example A- a 6" aero port would have 28.274in^2 of port area.

example B- a 5 1/2" x 5 1/8" port would also have 28.274in^2 of port area

example C- a 9 7/16" x 3" port would also have 28.274in^2 of port area

lets just say this port is 10" long, just to make our numbers easier to follow.

example A, the aero port, would have a circumference of 18.849". you take that circumference, and multiply by the length of the port, to get the amount of material surface area that is inside the port, and making contact with the air. in this case you have 188.49in^2 of actual material surface inside the port.

example B, this particular slot port would consist of two panels measuring 5 1/2" x 10" (110in^2 of surface area), and two panels measuring 5 1/8" x 10" (102 1/2in^2 of surface area). so in this port, you would have a grand total of 212.5in^2 of internal material surface that is making contact with the air.

example C, this particular slot port would consist of two panels measuring 9 7/16" x 10" (187 1/2in^2 of surface area), and two panels measuring 3" x 10" (60in^2 of surface area). so in this port, you would have a grand total of 247.5in^2 of internal material surface that is making contact with the air.

in summary:

example A- 188.49 square inches of internal surface

example B- 212.5 square inches of internal surface

example C- 247.5 square inches of internal surface

so, as you see, we have 3 different ports, with the same port area and the same length, yet we have big differences in the amount of internal surface that is making contact with the moving mass of air inside the port. the less material you have contacting the moving air in the port, the more efficient your port will likely be. beyond this, you can also do various types of prep work to the surfaces ass well, to make them as slick as possible to help slightly boost efficiency.

this is but one factor that is directly related to, and greatly impacts the overall efficiency of a port. this same ideology applies with ported enclosures, as well as bandpass.

this concludes todays dose of brain droppings.

Edited by Hugh G. Rection
  • Like (+1 Rep) 21
  • Thanks (+1 Rep) 1

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sweet Ima read this later, thanks for a useful post.

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Hope you keep adding to this, man.

I also hope members take the time to read it and learn a little something. Should be stickied.

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Hope you keep adding to this, man.

I also hope members take the time to read it and learn a little something. Should be stickied.

i probably will here and there.

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Pretty Simple. I got some ideas to try. I wish I just had the time and space to play lol. But If I ever get around to doing it I'll dump it in here :P

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This was a sweet read! Thanks for posting this ;)

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