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heyman421
07-16-2006, 10:39 AM
I can't believe winisd doesn't factor in port displacement :furious:

What's the point of using a program to design a box if it doesn't factor port displacement. :furious:

That was the most confusing part for me, and the entire reason i tried to use a program........

I almost built ANOTHER crap box :(

Decipha
07-16-2006, 10:45 AM
their is no point in a program designing a box for you... thats why you do it yourself and get it done correctly

xluben
07-16-2006, 11:03 AM
Port displacement is pretty basic math. You should be able to figure it out whether you use round or slot ports (with just a pen and paper and a little comon sense). If not I have small excel file that'll do either type of port. Basically all it will give you is net volume to type into WinISD (along with ports specs), and WinISD will tell you the tuning.

Download Box Calculator Via Xluben (http://www.jakobmetzger.com/misc/BoxCalculatorViaXluben.xls)

Just remember to use the top for round ports and the bottom for square ports.

If you are using a slot port and have certain height and width requirements try this site:

http://www.subwoofertools.com/forum/ported-box.asp

It works pretty slick and gives you a set of easy to build plans, but the tuning comes out a bit different than WinISD (many port calculators will be off by one or two Hz from each other due to slightly different equations being used).

DBfan187
07-16-2006, 11:08 AM
Port Displacement

if it uses of the sides of the box for one side of its port wall, then:

(port height) x (port length-wood thickness) x (port width + wood thickness) / 1728

if the ports in the middle of the box, and has its own walls, then:

(port height) x (port length - wood thickness) x [port width + 2(wood thickness)] / 1728

heyman421
07-16-2006, 11:32 AM
i realize how to find the displacement of the port, i just find it lame that even when designing a box from scratch with winisd, i have to fart around with port displacement and seeing what it's tuned at, rather than just telling it what i want, and headin' to the saw

helotaxi
07-16-2006, 04:21 PM
WinISD wasn't meant to be anything more than an aid to box tuning with the response graphs. For it to be a full blown box calculator that figures port displacement, net volume, gross volume, etc... it would have to incorporate a CAD element because port layout, material thickness and al that kind of stuff directly affects the amount of box volume displacedby the port. You re basically asking a FREE program to include a $1200 CAD suite with it and be fully integrated with it. Quit whining and get out a piece of graph paper and a calculator.

badstang123
07-16-2006, 06:15 PM
Quit whining and get out a piece of graph paper and a calculator.

lol. I can't agree more. I trust myself more than a program.

xluben
07-16-2006, 06:20 PM
WinISD wasn't meant to be anything more than an aid to box tuning with the response graphs. For it to be a full blown box calculator that figures port displacement, net volume, gross volume, etc... it would have to incorporate a CAD element because port layout, material thickness and al that kind of stuff directly affects the amount of box volume displacedby the port. You re basically asking a FREE program to include a $1200 CAD suite with it and be fully integrated with it. Quit whining and get out a piece of graph paper and a calculator.

x2

there are just way too many variables, not all boxes are designed the same.