need to learn

[RooTxBeeR]

I wish I knew the paper and pen way myself. Hopefully someone can jump in to show it is done.

why would you suggest a method you don't even know how to do?

And OP, there are a few guys on here who will help you out if you tell us the make and model of the equipment and goals of the system (daily, numbers, loud down low, etc)

Because it is always good to know where it actually comes from. It is not like I am telling to use the RE calc or do some bullshit method that won't work. If he took the time to learn how to really design a box, it would benefit him more than learning how to punch in numbers and get stuff punched back out for you.

[ChevyBoy95]

Ok, pen and paper can get a little messy but this site will help with tuning.

http://www.the12volt.com/caraudio/boxcalcs.asp

What you will need to do is...

1. Get your max dimensions, then if using 3/4" wood, take 1.5" off each dimension (to get internal sizing).

2. Multiply the 3 numbers together

3. Divide that number by 1728 (this will give you cubic feet)

4. With that cubic feet, figure out what would best suite that space, or downsize until it fits the current equipment.

5. You will need to get a port area size, usually 12-16 sq in of port per cube

5*** you need to understand that when figuring tuning with the calc above, every time you need to subtract the space taken by the port from the volume of the box, which will give you final net volume (what your subs will react in basically)

6. Play with port area (height and width) and length (depth) and try and find a target tuning frequency.

7. Once everything fits in the criteria all you can to is build it and test.

example of tuning.

say you have max 15" x 15" x 20"

1. subtract 1.5 from each -> 13.5" x 13.5" x 18.5"

2 & 3. multiply and divide by 1728 -> 1.95 cubic ft

4. will be good for a single 12in sub (after port displacement)

5. 1.95 cubic feet (say the port volume takes up .5 cubes[estimated]) so 12-16 sq per cube would be 1.35 * 12 and 1.35 * 16 -> 16-22 sq in of port goal

Here is where you play with the numbers for a while....

knowing you have 1.95 to work with, target size for a 12 is around 1.25-1.5 cubes net volume, you need 16-22 sq in of port, you have to plug in either tuning you desire to get port lengths and then subtract that from 1.95 to see what your net is, or the other way around.

[ChevyBoy95]

http://m.wikihow.com/Find-Cubic-Feet

Is this a good place to start.

I ask cause I always have ppl ask me to help them design a box and I 1. Don't want to ask u guys to design me a box for someone else 2 I don't like to send ppl here just for a box when in the long run that won't appreciate all the knowledge they could learn. Doesn't seem fair to waist Ur guys time.

that is a basic idea of volumes, which is important to learning about boxes and aero ports, yada yada yada. And you arent wasting any ones time, we are on this forum because we love car audio, whether it be teaching, watching, doing, or chatting.

[RooTxBeeR]

Ok, pen and paper can get a little messy but this site will help with tuning.

http://www.the12volt.com/caraudio/boxcalcs.asp

What you will need to do is...

1. Get your max dimensions, then if using 3/4" wood, take 1.5" off each dimension (to get internal sizing).

2. Multiply the 3 numbers together

3. Divide that number by 1728 (this will give you cubic feet)

4. With that cubic feet, figure out what would best suite that space, or downsize until it fits the current equipment.

5. You will need to get a port area size, usually 12-16 sq in of port per cube

5*** you need to understand that when figuring tuning with the calc above, every time you need to subtract the space taken by the port from the volume of the box, which will give you final net volume (what your subs will react in basically)

6. Play with port area (height and width) and length (depth) and try and find a target tuning frequency.

7. Once everything fits in the criteria all you can to is build it and test.

example of tuning.

say you have max 15" x 15" x 20"

1. subtract 1.5 from each -> 13.5" x 13.5" x 18.5"

2 & 3. multiply and divide by 1728 -> 1.95 cubic ft

4. will be good for a single 12in sub (after port displacement)

5. 1.95 cubic feet (say the port volume takes up .5 cubes[estimated]) so 12-16 sq per cube would be 1.35 * 12 and 1.35 * 16 -> 16-22 sq in of port goal

Here is where you play with the numbers for a while....

knowing you have 1.95 to work with, target size for a 12 is around 1.25-1.5 cubes net volume, you need 16-22 sq in of port, you have to plug in either tuning you desire to get port lengths and then subtract that from 1.95 to see what your net is, or the other way around.

I understood all of this for a very long time except 5. Figuring out how much port i needed. Now I see you say to multiply the net volume by 12-16 to get your range of port area. But how do I get the actual port volume without assumptions. That was always my problem. Could I just make a fake calculation, like you did, just saying 1.5cuft for a easy example. Figure the port area, then once I get the amount, take down the box to get it to match up? That was always the most complicated part to me.

Edit: Basically to sum up my drunk and high ramble, How in step 5 do I get a real, non estimated port area number to use in a real calculation. Once I get that, I can do a box in minutes on paper.

[ChevyBoy95]

Ok, pen and paper can get a little messy but this site will help with tuning.

http://www.the12volt.com/caraudio/boxcalcs.asp

What you will need to do is...

1. Get your max dimensions, then if using 3/4" wood, take 1.5" off each dimension (to get internal sizing).

2. Multiply the 3 numbers together

3. Divide that number by 1728 (this will give you cubic feet)

4. With that cubic feet, figure out what would best suite that space, or downsize until it fits the current equipment.

5. You will need to get a port area size, usually 12-16 sq in of port per cube

5*** you need to understand that when figuring tuning with the calc above, every time you need to subtract the space taken by the port from the volume of the box, which will give you final net volume (what your subs will react in basically)

6. Play with port area (height and width) and length (depth) and try and find a target tuning frequency.

7. Once everything fits in the criteria all you can to is build it and test.

example of tuning.

say you have max 15" x 15" x 20"

1. subtract 1.5 from each -> 13.5" x 13.5" x 18.5"

2 & 3. multiply and divide by 1728 -> 1.95 cubic ft

4. will be good for a single 12in sub (after port displacement)

5. 1.95 cubic feet (say the port volume takes up .5 cubes[estimated]) so 12-16 sq per cube would be 1.35 * 12 and 1.35 * 16 -> 16-22 sq in of port goal

Here is where you play with the numbers for a while....

knowing you have 1.95 to work with, target size for a 12 is around 1.25-1.5 cubes net volume, you need 16-22 sq in of port, you have to plug in either tuning you desire to get port lengths and then subtract that from 1.95 to see what your net is, or the other way around.

I understood all of this for a very long time except 5. Figuring out how much port i needed. Now I see you say to multiply the net volume by 12-16 to get your range of port area. But how do I get the actual port volume without assumptions. That was always my problem. Could I just make a fake calculation, like you did, just saying 1.5cuft for a easy example. Figure the port area, then once I get the amount, take down the box to get it to match up? That was always the most complicated part to me.

Edit: Basically to sum up my drunk and high ramble, How in step 5 do I get a real, non estimated port area number to use in a real calculation. Once I get that, I can do a box in minutes on paper.

that is the down fall to on paper, you dont see immediate results like on torres, you basically have to guess a bit. Say if overall volume is 2 cubes, you need 25 sq in of port for this 12 you have, and want 35hz and around 1.5 end volume. Well, you could do 5*5 = 25 and multiply by a estimated length (remember port walls take up space too), or go for an estimated volume, and work backwards. By hand takes time, but you can do them on the fly. The more and more you do, the easier it becomes in the guestimation side.

Others might do it different so i dont know.

[rsfm089]

Wow not trying to be lame but I need to buy a computer

[Weigel21]

LOL.

Don't worry, I think most of us on here would be saying the same thing.