Noob Port Question

[MeathooK]

When modeling ported enclosures in WinISD, is the "Vent Diameter" the inside diameter of the tube or outside diameter? For instance... 1.25" Sch 40 PVC is actually 1.66" outside diameter and 1.36 inside diameter

[greywarden]

personally, I've used WinISD for years to do boxes for my friends in HS and whatnot, but if you're building speakers use Unibox. It's so much more in-depth, but simple enough for WinISD converts to use, too. To be honest i think it's easier to use than WinISD

[billfitzmaurice]

When modeling ported enclosures in WinISD, is the "Vent Diameter" the inside diameter of the tube or outside diameter?
Inside. The diameter references the air mass within the port, so the outside diameter is moot.

[Chris Roemer]

personally, I've used WinISD for years to do boxes for my friends in HS and whatnot, but if you're building speakers use Unibox. It's so much more in-depth, but simple enough for WinISD converts to use, too. To be honest i think it's easier to use than WinISD

It's the I.D.

WinISD "beta" is simpler/easier to use, but once you get the hang of it, try the "Pro" (alpha) version, it can tell you so much more.

[greywarden]

I use the pro version because it's the only one that "kinda" works on windows 7...

[charlielaub]

When modeling ported enclosures in WinISD, is the "Vent Diameter" the inside diameter of the tube or outside diameter? For instance... 1.25" Sch 40 PVC is actually 1.66" outside diameter and 1.36 inside diameter

Since you asked this kind of question, I thought I would also bring up another good thing to remember about dimensions...

When modeling software (WinISD for you) says that box volume is *** ft^3 or whatever, this is the volume of the INSIDE of the box, and does not include the volume displaced by the driver cone, the driver magnet, any bracing, and the port. The model's box volume can be thought of as "free and available air volume" and these other things also occupy space inside the box. Always make sure to add up these "extra" volumes when you are designing the box so that you don' tend up making it too small.

Hope that is a helpful tip for you.

-Charlie

[MeathooK]

Thanks guys, I like WinISD quite a bit actually, but I'm going to check out UniBox as well. WinISD Pro tells quite a bit of information as well, just need a instruction guide on how to input new drivers as it gets really picky when you change values it calculated

[fastbike1]

If you can run Unibox, you might as well look at Jeff Bagby's Woofer Box and Circuit Simulator. I find it easier than Unibox to evaluate different tunings.

[Chris Roemer]

Thanks guys, I like WinISD quite a bit actually, but I'm going to check out UniBox as well. WinISD Pro tells quite a bit of information as well, just need a instruction guide on how to input new drivers as it gets really picky when you change values it calculated

No problem.

Make sure "calculate missing parameters" (or whatever it's called) is checked, then enter: Qes, Qms, (SKIP Qts, ISD will calculate and fill in a value that should be VERY close to what your specs are), Fs, Vas, Re, Le, Sd (the effective cone AREA, OR skip that one and enter the cone's effective diameter), Pe, aand Xmax. I THINK that's it!

Chris

[diy speaker guy]

...just need a instruction guide on how to input new drivers ...

It seems this question comes up every week or so. Doesn't anyone read the instructions anymore? (There's a section dedicated to this topic.)

[diy speaker guy]

Since you asked this kind of question, I thought I would also bring up another good thing to remember about dimensions...

When modeling software (WinISD for you) says that box volume is *** ft^3 or whatever, this is the volume of the INSIDE of the box, and does not include the volume displaced by the driver cone, the driver magnet, any bracing, and the port. The model's box volume can be thought of as "free and available air volume" and these other things also occupy space inside the box. Always make sure to add up these "extra" volumes when you are designing the box so that you don' tend up making it too small.

Hope that is a helpful tip for you.

-Charlie

This is a good note for beginners, but you didn't mention stuffing (or lining). The volume occupied by stuffing material can be considered "free and available air volume", you don't have to add any more volume to accomodate the stuffing like you do for the other solid objects in the box.

While this may seem super obvious, I've seen the question asked more than once...

[MeathooK]

Oh..haha my sentence came out wrong. I meant to say I know how to input new drivers into WinISD, but for the person who opens it for the first time it can be pretty frustrating. Thanks though.

[Æ]

Doesn't anyone read the instructions anymore?

No, just pop it into the microwave oven and press the button.

[Altec Best]

inside. The Diameter References The Air Mass Within The Port, So The Outside Diameter Is Moot.

+1 ;)