Determining port efficiency

[Christopher Cleveland]

Hey fellas I'm just beginning to learn more of the advanced things about ported enclosures. My question today is, is the total port surface area the main determining factor of its effiency, or does the shape have something to do with it as well? My main concern is between triangle, square and round ports. Also would that mean that all three of those styles are more efficient than a slot port of the same port area? Thanks

[dolarbilz]

http://www.stevemeadedesigns.com/board/topic/189867-understanding-ports-a-lesson-in-dimensions-vs-efficiency/?fromsearch=1

Here you go

[Christopher Cleveland]

Hey thanks man, I read through that before but they lost me when they started getting into flared aeroports and using different sized ports in the same enclosure and whatnot. Just wanted to get to the point mainly concerning if there are any detrimental effects from the sharper angles of the triangle shape specifically. Should have clarified that. But I'll read through it some more. Basically how I understand it right now is, in order from least efficient to most efficient goes: slot, triangle, square, and round. I'm considering going with a triangular port for the aesthetic tradeoff, I think it looks pretty sweet, also since it's more efficient than a slot, which is pretty much all iv ever heard. Should have posted this on that thread instead of making a new one. My bad.

[mrd6]

Something to keep in mind: if you are able to get enough port area (surface area of the port opening) then the port shape/ geometry becomes much less inportant

[Triticum Agricolam]

A triangle port is usually NOT going to be more efficient than a slot port, though it's going to depend on the shape of the triangle and the aspect ratio of the slot port you are comparing it to.

If you want a relatively easy way to compare port shapes calculate the ratio of port area to internal perimeter.

For example a 4" round port has 12.56 sq in of port area and - 12.56" perimeter (4 x pi) for a 1:1 ratio.

A 2" X 6" slot port has 12 sq in of port area and 16" of perimeter for a 1:1.33 ratio.

A 4" X 6" right angle triangle port has 12 sq in of port area and a perimeter of 17.21" for a 1:1.43 ratio.

Lower ratios are better.

[Christopher Cleveland]

Alright, I was doing some calculations at work last night, comparing a 14x2.5x 27 deep slot port to a 8.25x8.5x11.875x 27 deep triangular port and figured the triangular port would be the more efficient of the two in this particular example? I would use a square or round port if I was a competitor for best performance, but this is my daily driver and I kinda just want something aesthetically different to show my buddies and shit, while still being somewhat conscious of actual performance. I dunno. But yes, thanks for the input gents, and Triticum, I would have inboxed you with this matter but I figured I'd ease up off blowing up your inbox since iv been hitting you up a lot lately haha. Alright guys thanks again.

[Christopher Cleveland]

And I missed your key word there "usually" not as efficient. But I see not always, if my calculations and understanding were correct. So port area to internal port perimeter ratio. 1-1 is optimal, with only marginal performance loss up to 3-1 ratio if I remember from one of your messages right?

[Triticum Agricolam]

Yup, that's right, there is only marginal performance loss up to a 3:1 slot port.

What mrd6 said though is definitely true, most port efficiency problems are easily fixed/reduced by just increasing port area. With enough port area port shape becomes much less relevant.

[3vil]

I feel the need to point out that your example for a circle port only really holds true for a 4" round port. Any larger and the ratio starts changing. 4" circles just have a little magic about them.

[Triticum Agricolam]

I feel the need to point out that your example for a circle port only really holds true for a 4" round port. Any larger and the ratio starts changing. 4" circles just have a little magic about them.

You are totally right.

With any shape of port, the ratio is going to get larger as the port size increases. Its only useful when comparing port of equal or very similar area.