posted
Ok Well we are beating around the bush quite a bit. I do remember how to figure Length for a port but that is only with one port. I found this in a old post (port tuning formula)
R = radius of port Vb = volume of box Fb = tuning frequency.
Here with the ABC box I have no problems The total box volume will be 2.77Ft^3 with out port or diver dis. With them in there it will be 2.4Ft^3 making box a=1.6Ft^3 and b=.8Ft^3 like as printed in the book. Ok please help me here. Tell me the port I need to make. I have 3" PVC so lets use that. If you can give us the fomula for multi ports in a box.
Cut the box volume in to as many ports as you want. Since you want 2 cut it in half. Figure the port for one of those halves. Cut another for the other half.
You will notice that the more ports you add the length gets longer.
Some people think you can just take two ports and sum their cross-sectional areas, and figure for a port of the same size. This would sound reasonable, but it can lead to serious mis-tunings in some cases since this method doesn't take into account frictional loses.
Due the math and see what you come up with. If you have further trouble I will walk you through it. But you can't beat first hand experience.
Hope this helps.
------------------ ******************* Founder: Street Sounds Car Audio Club ******************* If It Don't Read 150+ it Ain't Loud......
Posts: 289 | From: Howell, MI | Registered: May 1999
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