View Full Version : ExpoSport's (Torres) GUI-based Box Tuning Calculator

04-07-2010, 11:36 PM
here's a GUI-based box tuning calculator i've been working on for a while. some may have seen it, i have it up on other forums but i finished a pretty nice sized update for it a little bit ago. pretty sure all the lil flaws and tweaks have been worked out, so i'm gonna post it here. if you dont like it, that's cool just dont use it. it's taken a long time to get it to where it's at and i'm happy with it. i'm gonna copy the original post, there's a lot to type lol.

FIIIIIINALLY!!!! finally freakin done with this update. only took 4 months lol. got a whole new slew of things. here's a screen shot of what it looks like (minus a few minor differences from this post date)

sorry for such the large size. it was hard squeezing so much into such a small box. i do realize that on some resolutions the program wont display fully on the screen. but maximizing will fix that until i can figure a better layout or a way to fix it. it should have pretty much any suggestion that was thrown my way that i could find useful. along with a couple last minute changes, like the desired net/gross volume boxes

here's the download link to the program:
Box Tuning Calculator Download (http://bit.ly/bO6hV7)
***you'll need the most up to date .net framwork for this program to work. click this link to get it***
.NET Framework (http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=333325fd-ae52-4e35-b531-508d977d32a6)

there's port cut sheets in there, but one thing i did NOT include are cut sheets on how to cut the port if it bends. there's too many different ways to cut the sheets, and the coding to go into that would be too tedious to deal with. maybe at another time down the road. right now i want to get it uploaded and not have something silly holding it back. plus, if you're building a speaker box, i'm sure you can go take some measurements in the box and see what the port should be :)

i've also included a FAQ/tip sheet with it this time around. so if you get confused with something, click there first. if you're STILL confused, send me a PM with any questions. with that being said, i'm still going to paste all the contents of the FAQ here.

Box Frequency Tuning Calculator - FAQ/Tip Guide

1 - First and foremost, the RE calculator is *not* spot on, and is limited in design, so no, it will not match this calculator.

2 - When doing an oddly shaped box such as a fiberglass box, or you know the volume of a certain box you have in mind
that you want to build, put the net volume in the 'Desired Net Volume' box. This will bypass all dimensions entered
preventing you from having to guess dimensions to get a certain net volume and will allow you to tinker with different
port sizes and tuning. So if you know you want a box with 4 cubic feet of net volume, enter '4' into that box and it
will allow you to adjust tuning accordingly to that specific volume. Keep in mind that any displacement nor port volume
is NOT subtracted from this total.

3 - The 'Desired Gross Volume' box acts much like the Desired Net Volume box, except all displacements are taken into

4 - If the number of aero ports is greater than 0, then that automatically gets taken into effect and the calculator ignores
the dimensions for slot ports.

5 - The '# of Common Port Walls' box refers to how many sides of the box are going to act as sides of the port.

6 - Port length uses the box wall or baffle(s) as part of the port length. So a port that is 10" long with one baffle using .75"
wood will only need to be 9.25" long as the box wall or baffle(s) will account for the other .75". If using two baffles,
then it would be 8.5" long as the baffle will account for 1.5" of port length.

7 - Port walls are defaulted with a .75" thickness.

8 - Regular square/rectangle boxes do not need any numbers entered into the 'Height 2' or 'Depth 2' boxes.

9 - Pressing 'Enter' will prompt the program to print.

10 - Slot port area range is based on 12-16 square inches of port per cubic foot, while aero ports are based on 9-13 square
inches per cubic foot.

10 - On the cut sheets of boxes with different depths and heights, you'll notice 'H1' or 'D2' next to the measurements.
These represent which dimension is which. Here are two pictures to illustrate:

Box with one height, but two different depths: http://img59.imageshack.us/img59/8449/angledcutsheet1.png

Box with two heights and two different depths: http://img163.imageshack.us/img163/607/angledcutsheet2.png

If they do not go in the proper order, the sheet will not come out properly.


--Here is the formula the calculator uses (the same on displayed in the program itself):

--The following are links that illustrate how each ported box is taken into effect in the calculator (sub and port position can be upwards with the same effect):

1 - Port with 0 common walls: http://img693.imageshack.us/img693/6474/independentport.jpg

2 - Slot port with 1 common wall: http://img341.imageshack.us/img341/9939/bottomportbox.jpg

3 - Slot port with 2 common walls: http://img94.imageshack.us/img94/2017/middleportbox.jpg

4 - Slot port with 3 common walls: http://img246.yfrog.com/img246/6968/slotportbox.jpg

--The images were made with Google Sketchup. Free to use: Google SketchUp (http://sketchup.google.com/)

should be 99% debugged (i think). but after staring at the same coding for so long, things are bound to slip by. so IF you do find something that seems out of place, PM me about it please. and only if you're certain about it. i dont want to go check something or explain how it's done several times over because it may be coded a certain way that you may be thinking differently. that'd be too tedious for me to do constantly.

hope you guys like it :)

04-09-2010, 07:38 PM
wow i'm surprised there's not more interest in this :wacky:

04-09-2010, 09:05 PM
I like this alot better than the RE one, but, why is 1.5 added to the port length calculations? it should only be .75(the thinkness of wood used) because you only have to add the opening of the port.

04-10-2010, 04:44 AM
.75 is added for a slot port with 3 common walls (a port that shares 3 box walls as part of the port. if it shares 1 or 2 sides, then more wood is used for the port, ending up with more displacement.

if you mean port length, then that's for end correction, which is half of the port width (or height, depending on how you look at the port. basically the smaller port dimension). so 3" wide would be 1.5" of extra length for end correction. or if it was 5" wide, 2.5" of extra length for end correction

04-12-2010, 11:42 PM
so I made a 5x5 port, and i calculated "0" into your calculator for port length, do I need to add 2.5 to the length of the port? or is it 0? (port uses one side of box) because 2.5 is plugged into the equation

04-13-2010, 04:51 AM
a port should not be 0" long. if it's a slot port, 2.5" will be automatically added to port length for end correction, but 0" does not really count as a port. you need an actual port for it to be correct. if 0" gives you ANY sort of real life tuning, then it must be a low low amount of port area for the box, which also needs to be addressed

04-13-2010, 08:47 AM
so then I have to add 2.5" onto this port? also pictured is what I used form your calculator.


04-13-2010, 12:57 PM
technically yes you would. but for a port to be effective, there needs to be more of a physical port in the box rather than a hole in the box. but look on the output boxes on the right -- based on 12-16 sq inches of port per foot, you should have 97-129 sq inches of port, whereas you have 25. you need at least 4 times more port area than what you have. just to get an idea, put 10 inches in the height and width for the port to get 100 sq inches, then look at the tuning. you'll see that you will need a port length

04-13-2010, 01:04 PM
and end correction is a number that gets added into the port length in the equation of the formula when doing slot ports. it does not need to be figured in manually or physically. say that port was 10" long, it'd be physically 10" long but the sub will *think* that it was 12.5" long. but you would not need to type in 12.5" for port length

04-16-2010, 12:45 PM
one more bump before i let it get buried

04-16-2010, 12:50 PM
Thanks for the program...I will check it out

I'm sure you spent some time on this, I'm sure many will find use out of it. Thanks for your effort

04-16-2010, 01:26 PM
Awesome, I just came on here ready to post up my RE calc design along with a bunch of problems/questions I had with it due to its limitations and this is here waiting for me. Thanks a ton for your time and contribution, can't wait to see how it comes out

EDIT:: Maybe I am not using it right, but to be honest thus far it has been much more difficult/frustrating to use than the RE calc. First, when I try to use your feature Desired Net Volume it is written: "This will bypass all dimensions entered preventing you from having to guess dimensions to get a certain net volume and will allow you to tinker with different port sizes and tuning. So if you know you want a box with 4 cubic feet of net volume, enter '4' into that box and it will allow you to adjust tuning accordingly to that specific volume". This sounds great but when I enter my desired net volume not one value in your calculator shifts besides the port area range, port area per foot, and the tuning frequency. This is absolutely no help in determining how to make adjustments, you have to guess around once again with your port dimensions to re-correct the tuning frequency, and then on top of that, it appears to mean nothing because none of the cut sheet list values change, and the box dimensions have been ignored so changing them means nothing, and now you have no idea how to build your actual box to fit this desired net volume... all you have done is picked a desired net volume and calculated port dimensions based on your desired frequency...

My apologies for my frustration, if you can shed some light on this please do. Thanks! -Mat

04-16-2010, 01:36 PM
woop woop! thanks guys :) hope it works well for ya

04-17-2010, 10:36 AM
Any news on the above question? I am just curious if you got this figured out?

04-17-2010, 12:48 PM
all you have done is picked a desired net volume and calculated port dimensions based on your desired frequency...

knils....that's working exactly how it's supposed to. picking a desired volume if you know how much space you want to give you speaker(s), and tuning it to that volume. it's your job to figure in the dimensions to achieve that. changing box dimensions would be virtually impossible because there would be so many ways to go about doing so. then the port dimensions would have to fit right and both would be pretty much random and not come close to the original design the user was trying to attain. i'd have no way of knowing what dimensions to make them to fit in their car/truck. it wasnt really meant as a text box that you work towards or does the work for you, it was more for fiberglass enclosures or other oddly shaped boxes where you cant take a measuring tape to get any solid dimensions. basically where packing peanuts would come into play. then put that volume from the peanuts in one of the boxes then figure tuning from there without changing the value of the net volume. or if someone says they have xx.xx cubes net volume and want to know the tuning of their box and give port dimensions, you dont need to plug random numbers in to get that volume and try to figure out their tuning.

designing boxes period is kind of like a guessing game regardless. you put dimensions for a box to get xx volume, put in port dimensions that fits that volume, then when you add length to tune it, it lowers net volume, which in turn raises port surface area and raises tuning. which then requires less port area or shorter port length to maintain that original tuning which raises net volume. change one value and all the others change as well. this is just here to help simplify doing all that

hope that answered your questions. i think there was confusion with how the boxes were meant to be used

and thanks for bumpin this fukn. my subscription e-mail didnt e-mail me since it was an edit and not a post :p i dno when i would have seen it

04-17-2010, 01:51 PM
why does clicking sub upward lower the port length by 10"?

04-17-2010, 03:09 PM
because the port needs to bend, so the 'physical' length just needs to be shorter but if you measure down the middle of the port you'll notice it's the same length

04-17-2010, 04:06 PM
Cool, that's about what I figured...

04-17-2010, 05:36 PM
So if you have a bend in the port then where does the physical port length number come from?

ok i make my port length 16" and heres what i get
http://img710.imageshack.us/img710/7905/box1y.png (http://img710.imageshack.us/i/box1y.png/)

if i make my port 17" then i get this
http://img62.imageshack.us/img62/744/boxm.png (http://img62.imageshack.us/i/boxm.png/)

why does the physical port length get smaller when i make the port length longer and need a bend?

04-18-2010, 06:56 PM
physical port length is the length of the wood. in the first one, the port does not need to bend so therefore it's the full length. in the second one, it has to bend, so it doesnt need to physically be as long as you have entered in the box. somewhat similar to this:


caption should explain it. but the physical port there is 10" long, while you're getting a longer actual port length (the small purple length is end correction of the port)

04-19-2010, 07:36 AM
That still doesnt make sense to me. So if i need a bend in the port, then my piece of wood needs to be smaller than if i didnt have a bend?

04-19-2010, 12:43 PM
I think what he is getting at (if I understand correctly) is that the physical port length and what the woofer actually thinks the port is are two different things and he is accounting for the little extra length you "theoretically" get in certain situations............... Right?

04-19-2010, 08:23 PM
that is exactly right. if you look at the diagram i posted, the physical length is 10", yet the *actual* length is longer (measured down the middle). if you made that box say twice the size with the port staying the same, then the curve in the box would not technically extend the port length since it's much further away. it'd be just 10" (minus end correction). you wouldnt have that purple and brown length measurement added into the port length. so the port length is the same, just the material needed to make the port is different.

05-02-2010, 10:57 PM
I made my own tiny program in excel but this absolutely blows it out of the water. I found it relatively easy to use once I started seeing how the output numbers changed as I messed with the other variables.

This should be a sticky. Or at least included in a sticky for ported box calculators.

05-03-2010, 12:20 AM
:D thanks man glad you like it!

05-03-2010, 07:13 AM

06-04-2010, 02:38 PM
just a little bump is all :)

12-30-2010, 09:19 PM
new years bump!!

and call for a sticky, this is a great prorgram

12-30-2010, 11:06 PM
thanks!! appreciate the kind words. soon, hopefully really soon, i'm going to have metric worked into it for people across the pond. plus a new thing or two, more so just visual things.