Port Length Calculator help

[Dexter Chaos 14]

I have designed a box using Torres.

 

Under port dimensions I have entered 33.5 as my length

 

In the calculator it has a Physical Port length of 25.

It also states that this will require me to make a bend but at 25 inches

In my mind I was looking at it that I will make the two peices of wood a total of 33.5" long.

 

1. What is the difference?

2. Which should I use to make my cuts with?

3. Am I looking at that incorrectly?

 

I am just confused now.

 

 

 

[A.SMALL 17]

Lol me and a friend had this same conversation yesterday. From what I understand the "Physical Port Length" is the total length of the inner L and that is the length you want your port cuts to be.

The desired length that you enter under the inner port deminsions is the actual port length that you will get from using the "physical port length".

So in your case the port lengths you cut would have a total length of 25 yielding an inner port length of 33.5.

The way it was explained to me is the actual length of the port is measured down the center of the port and is an average between the physical L and the outer L created by the outer box walls.

Not sure if I confused you more but maybe someone else can explain it better lol.

Edited April 22, 2013 by A.SMALL

[Jason Witt 65]

What is the inner port width?

[Dexter Chaos 14]

What is the inner port width?

 

7 inches

[Jason Witt 65]

Okay, you are going to use the total port length of 33.5 inches and make the L 7 inches from the rear wall of the enclosure. You want the back port wall the same amount of space as your inner width (seven inches) from the rear wall of the enclosure.

[SPL_Man 20]

been a long time since i read up on this but iirc port length is measured in the middle of the port width & not by the "L" bend

[Jason Witt 65]

been a long time since i read up on this but iirc port length is measured in the middle of the port width & not by the "L" bend

How does this work? If it is seven inches in width back, why would you want the port wall 3.5 inches from the rear wall of the enclosure? To my understanding, half width is okay if you do not have any bends. The port would just go straight back.

[SPL_Man 20]

say if a port is 4" wide u measure in the middle which is 2" to get your length & not along the L

[Jason Witt 65]

say if a port is 4" wide u measure in the middle which is 2" to get your length & not along the L

Every enclosure I have built, I have the width of the port the same, before and after the L. I have never had any issues.

[A.SMALL 17]

been a long time since i read up on this but iirc port length is measured in the middle of the port width & not by the "L" bend

How does this work? If it is seven inches in width back, why would you want the port wall 3.5 inches from the rear wall of the enclosure? To my understanding, half width is okay if you do not have any bends. The port would just go straight back.

He's not saying the inner port wall needs to be 3.5 inches away from the rear he's talking about measuring the "total port length" when you measure an L port you measure down the middle between the inner L and Outer L to get the total length. Here's a rough illustration that I found...

 

Edited April 22, 2013 by A.SMALL

[Jason Witt 65]

 

been a long time since i read up on this but iirc port length is measured in the middle of the port width & not by the "L" bend

How does this work? If it is seven inches in width back, why would you want the port wall 3.5 inches from the rear wall of the enclosure? To my understanding, half width is okay if you do not have any bends. The port would just go straight back.

He's not saying the inner port wall needs to be 3.5 inches away from the rear he's talking about measuring the "total port length" when you measure an L port you measure down the middle between the inner L and Outer L to get the total length. Here's a rough illustration that I found...

I know what you are saying. Total misunderstanding on my part.

[SPL_Man 20]

my bad if i didnt explain it too clearly & confused anybody but that diagram illustrates exactly what i was saying

[Dexter Chaos 14]

This is how I understand it. But when using the calculator I would only have to make my second port length 1 inch long. when I change its actual lenght using torres it still states being a bend. Even if I change my measurement to keep those values correct. I hope I am saying this clear.

[Jason Witt 65]

Compare those results with another calculator and see what you get.

[A.SMALL 17]

So are you asking how is it considered a bend if it's only 1 inch?

 

A screen shot would help us see what you're talking about .

[Dexter Chaos 14]

 

 

Maybe this will help me

[A.SMALL 17]

I think baffle displacement is what's throwing you off. To keep your width of 7" internal the first port piece needs to be 25.5" long. Torres is subtracting the triple baffle you're using from the physical port so that leaves you 25.5-2.25= 23.25 add another inch for the second piece and you get the 24.25 that its showing. If you meant to double baffle you should have just used .75 for your baffle thickness. I believe ..

Edit: the second piece wouldn't be an inch long it would be .25" long because the .75" thickness of the first piece has to be included in that total length = 1" and in this case I wouldn't either bother attaching a quarter inch piece of wood won't make much difference in tuning.

Edited April 22, 2013 by A.SMALL

[A.SMALL 17]

So torres isn't including the extra baffles in the "physical pot length" ..