- Thread Starter
- #2
Anyone? Need this kinda quick..
AutoMediaPro
10+ year member
AudioHolic
- Thread Starter
- #4
Already have tried that..how does that do port area and design a box..
perfecxionX
10+ year member
CarAudio.com Veteran
ive been trying to find this also, i dont know why this info is so hard to find
ngsm13
5,000+ posts
BSEE
Ok, I'll type out a post. Hold on a min...
nG
nG
ngsm13
5,000+ posts
BSEE
To design a ported box:
You need to know how to perform simple algebra. This assumes .75" MDF, and a slot port using one of the box walls as a port wall. //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif
Use WinISD Pro, don't pay any attention to the driver selection or graph. They're useless. Pick an arbitrary driver.
Terms:
NET Volume: This is the volume your subwoofer actually "sees". NET volume is AFTER all displacements (port displacement, driver displacement, wood displacment, bracing, etc...).
GROSS Volume: This is total volume, including all displacements. What space the box actually takes up.
Port Area: The Width and Height of the port, multiplied together. This is 2dimensional, hence the term area.
1. Figure desired NET volume, port area, and tuning.
2. Write down max, or desired Width x Height x Depth.
3. Pick the dimension of 2 sides you want, and leave the third side as a variable. (s) Multiply the two sides together and write this off to the side.
4. Open up WinISD, and pick an arbitrary driver. Continue to ported.
5. Type in your desired box volume, this is the NET Volume, as well as desired tuning.
6. Go to port tab, type in desired port area. It will give you the needed port length.
7. This is where simple algebra comes in. Take the port width and add .75" to it for the port wall. Now find out the volume of the port. Do this by multiplying: (Width(+.75) * Height * Length) / 1728 | This is your port displacement.
8. Take your NET volume, add port displacement, add sub displacement, add any other displacements (bracing, etc.) This is you internal GROSS volume. This is how big the box needs to be internally for correct NET volume and tuning.
9. More Algebra. You will be solving the following algrebraic equation for (s), this will give you the internal dimension of the last side (the variable you chose.) Actually, here is the equation solved for (s).
Equation:
S = (GrossVolume * 1728) / (Product of remaining two sides)
Voila. You have the internal dimensions, NET Volume, port area, port length, and tuning for your enclosure.
//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif.
Any questions, let me know.
nG
You need to know how to perform simple algebra. This assumes .75" MDF, and a slot port using one of the box walls as a port wall. //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif
Use WinISD Pro, don't pay any attention to the driver selection or graph. They're useless. Pick an arbitrary driver.
Terms:
NET Volume: This is the volume your subwoofer actually "sees". NET volume is AFTER all displacements (port displacement, driver displacement, wood displacment, bracing, etc...).
GROSS Volume: This is total volume, including all displacements. What space the box actually takes up.
Port Area: The Width and Height of the port, multiplied together. This is 2dimensional, hence the term area.
1. Figure desired NET volume, port area, and tuning.
2. Write down max, or desired Width x Height x Depth.
3. Pick the dimension of 2 sides you want, and leave the third side as a variable. (s) Multiply the two sides together and write this off to the side.
4. Open up WinISD, and pick an arbitrary driver. Continue to ported.
5. Type in your desired box volume, this is the NET Volume, as well as desired tuning.
6. Go to port tab, type in desired port area. It will give you the needed port length.
7. This is where simple algebra comes in. Take the port width and add .75" to it for the port wall. Now find out the volume of the port. Do this by multiplying: (Width(+.75) * Height * Length) / 1728 | This is your port displacement.
8. Take your NET volume, add port displacement, add sub displacement, add any other displacements (bracing, etc.) This is you internal GROSS volume. This is how big the box needs to be internally for correct NET volume and tuning.
9. More Algebra. You will be solving the following algrebraic equation for (s), this will give you the internal dimension of the last side (the variable you chose.) Actually, here is the equation solved for (s).
Equation:
S = (GrossVolume * 1728) / (Product of remaining two sides)
Voila. You have the internal dimensions, NET Volume, port area, port length, and tuning for your enclosure.
//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif.
Any questions, let me know.
nG
j3bus2k3
5,000+ posts
Si vis pacem, para bellum
^that should almost be stickied at the top for newbies...
ngsm13
5,000+ posts
BSEE
To continue. To layout the box.
I always use the sides as ultimate overlap. The non-port sides as one overlap. And I let the port side, slide INTO the other sides.
We'll assume a car enclosure.
So. Write down INTERNAL dimensions.
Sides: Take depth+1.5, and height+1.5
Top/Bot: Take depth+1.5, and width
Back: Take height, and width
Front: Take height, and width - portwidth
This is a simple car enclosure, assuming subs/port firing forward or rearward.
nG
I always use the sides as ultimate overlap. The non-port sides as one overlap. And I let the port side, slide INTO the other sides.
We'll assume a car enclosure.
So. Write down INTERNAL dimensions.
Sides: Take depth+1.5, and height+1.5
Top/Bot: Take depth+1.5, and width
Back: Take height, and width
Front: Take height, and width - portwidth
This is a simple car enclosure, assuming subs/port firing forward or rearward.
nG
ngsm13
5,000+ posts
BSEE
IonSQL
10+ year member
CarAudio.com Veteran
Good writeup //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif
Only thing I would add is something about how to decide how much port area to use, or at least what the "rule of thumb" is... that seems to be a Q that is asked often
Only thing I would add is something about how to decide how much port area to use, or at least what the "rule of thumb" is... that seems to be a Q that is asked often
ngsm13
5,000+ posts
BSEE
Supposedly the rule of thumb is 12-15sq. in. per cubic foot.
I like lots of port. I also usually go by subwoofer size, available volume, and enclosure size.
My last port 15 enclosure was 4.5cubes NET @33hz with 90 sq. in. of port... hehe.
nG
I like lots of port. I also usually go by subwoofer size, available volume, and enclosure size.
My last port 15 enclosure was 4.5cubes NET @33hz with 90 sq. in. of port... hehe.
nG
perfecxionX
10+ year member
CarAudio.com Veteran
thanks alot bro
so tuning is just a combination of port area and port length in relationship with net volume?
so qes, qts, etc doesnt have much of an impact outside of competition? (or not much impact inside winisd?)
i got the impression it was more complicated then this
what do people do when they get a 10" type r to do 151db?
so tuning is just a combination of port area and port length in relationship with net volume?
so qes, qts, etc doesnt have much of an impact outside of competition? (or not much impact inside winisd?)
i got the impression it was more complicated then this
what do people do when they get a 10" type r to do 151db?
- Thread Starter
- #15
Cool thanks, only a few questions. Do you have to use winISD Pro or will winISD work? And what do you mean by "pick an arbitrary driver, and continue to ported"? I am not very familiar with winISD.
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