End correction theory. How thick of port wall to stop end correction. read

[vehementSPL 10+ year member]

Well As it says. Like say I am using one end of the box as part of the port. I know end correction and how it works. But there is a question. If I was to screw a piece of wood there the same length as the rest of the port, how thick does this wall as where end correction is no longer an Issue. Like for example (I know not possible) but if the port wall you used was 1/1000th of an inch thick it wouldn't affect the end correction most likely I would think. The theory in question is assuming you are using one end of the box and just attaching a piece of wood to the side of the box that is using the box as part of the port to just create a port the same length as the rest of the port without end correction. I have approx 500 inches of port and obviously don't want to shrink it due to lowering the tune. the port is 12h x 41 high. the origional port design was 4 inches deep. but used 3 sides of the box as port. Top/two sides. Port is all the way across the top of the box. I am trying to tack 3/4inch mdf to the box all the way around the inside 4 inches deep. To make the total effective port depth truely 4 inches and not 10. I am thinking 3/4 would be enough. But surely there would have to be a thickness where it wouldn't affect end correction. There will be NO distance between the port walls and the side of the box. There will just be a 3/4 inch thick strip tacked on the side of the box. I would think this would work... .But for some reason doesn't seem right to me... not enough width from the side wall..... or perhaps I just have questioned it so much that it doesn't look right

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[vehementSPL 10+ year member]

Anybody? I know I have been asking a lot of iffy questions lately. Just sometimes I like to question what I know to put myself into check to make sure I am not getting too off the correct path with some of my theories. And I figured since my 4th order is what I am using currently I figured perfect example

 

[pr-festiva 10+ year member]

i think the small 4 inch lip would just be more like a sharp speed bump to the moving air and you would probly get about the same end correction ,but im not sure.I could try it in my BP but i dont want to lose any port area either

 

[vehementSPL 10+ year member]

i think the small 4 inch lip would just be more like a sharp speed bump to the moving air and you would probly get about the same end correction ,but im not sure.I could try it in my BP but i dont want to lose any port area either

Yeah this was kinda what I kinda wonder. In theory port operates on resistance so that 3/4 lip should be plenty. But there has to be a limit on how thin you can go since end correction is an outside factor that affects the tuning rather than just the typical resistance felt from the port opening . So with adding this into the equation it does add a bit of confusion for me. I understand how to figure out end correction But I don't understand gobbs about it.This is why I am not sure if that 3/4 lip is enough to differentiate the side of the box from an actual port

 

[vehementSPL 10+ year member]

crap posted twice

 

[pr-festiva 10+ year member]

maybe putting a angle on the inside edge?? so it would flow better

 

[pr-festiva 10+ year member]

i wonder if its like the rule for the closeness of a port to an inside wall

 

[audioarsonal 10+ year member]

Just tacking a 1x3/4" piece all the way around the three sides won't create a port.How big is the box that you need 500sqin of port?Maybe you have to much port and its acting like a giant leaky box instead of a ported inclouser.

 

[pr-festiva 10+ year member]

he's running a bandpass,,I have about 500 inches of port for mine too