Veteran Box Builders

[cgrez33]

So I have a pretty general question.

I know alot of guys now a days design and build boxes based on programs and plugging in numbers etc.

But several SPL Veterans and other guys tend to just go at it, most never use a program or some haven't even heard of it lol.

Does this just come from experience in doing it so long?

[audiofanaticz]

For a basic box paper and a pencil is fine.

Unless you want to be sitting there for hours doing some elaborate design, a program to "just punch in numbers" is going to be a lot quicker..

Besides you have to know the numbers you are punching in.

Also even while using some sort of program you still gotta bust out the pencil and paper to get displacements figured out for any 45s or other bracing, or draw it in sketchup (which for me takes years and not worth it).

[Triticum Agricolam]

With just about anything, there are always more than one way to reach success. The way a lot of the SPL veterans got there was through significant trial & error.

Using software can definitely eliminate a lot of trial and error, but it still requires significant experience to be able to properly interpret the results.

At this point I wouldn't even consider designing a box with the use of modeling software. That's just how I do it though, people have to do what works best for them.

[ShadeTreeMechanic]

I usually crunch the numbers on paper and then verify with a box calculator. I won't buy a driver without crunching the numbers first. Figuring it all out is the fun part.

[Tarball]

I do volume and tuning calculations on the computer then back to graph paper to design the box.

[Nightshade]

I determine how much internal volume I want. I use a predetermined amount of port area. So next I figure out how long the port needs to be to tune where I want to. For example I just built a box for my Sundown X15. I knew that I wanted exactly 4.25 cubes after port and woofer displacement. I knew I was going to use a single 8 inch aeroport which is 50.24sqin of port. That gives me 11.82sqin of port per cubic foot of volume.

Now I use a calculator telling it that I want to use 1 8 inch aero, have 4.25 cubes of volume, and I want to be tuned to 34.5hz. The calculator then says I need 21.75 inch long port from flare to flare to get this tuning. Now that I have my port length I figure out how much volume it will displace. Once I come up with that I add in the sub displacement and any bracing and get my total displacement figure.

I then move on to how much room I have to work with. Lets just say I have 40 inches wide, 18 inchez tall, and 20 inches deep. I figure out the combinations of those dimensions that will be my desired box volume and my displacement figure added together. Let's say that is 36.5 wide X 18 deep X 18 tall. When multiplying 1.5 inches is subtracted from each dimension since I use .75 inch wood. Those numbers give me 9528.75 in cubed. Next, I divide that number by 1728 (which is 12^3 number used for box volume) and I get 5.5cuft. Then I subtract my displacement from that which lets say is 1.25cft. That will give me exactly 4.25cubes, which is what I wanted. However, let's say that number were larger or smaller, then I would go back and adjust the box dimensions until my number is where I want it to be.

I won 2 NSPL Car class titles with boxes I designed this way as well as all the daily boxes I use and any I have designed for others.

That is my process. I do not like using a box calculator but I do rely on the port length calculator.

[jk13]

I do not like using a box calculator but I do rely on the port length calculator.

This is what I've always done. Figure volumes and spaces myself and plug into a port length calculator, minor as possible adjustments from there. I do a lot of stealth systems and sometimes small compromises are the name of the game.

significant trial & error.

Cannot be stressed enough. Even today (with computer help) at the elite level it's almost never a "one and done" for those at top of the heap. And once you're loud, staying loud is a whole 'nother issue.