# Basic Box Building Tutorial



## bfowler (Nov 25, 2009)

I didn't see one here so i copied and pasted mine over from phoenixphorum.com. this is a box i built for my PG xenon 10d2

I know it is probably common knowledge here, but im sure it will help someone. 

open to constructive criticism and advice.


without further delay: 

Bfowlers big bad basic box building butorial. er, tutorial

Avoid Alliteration Always

Materials used:

-lots of 1.25" corse drywall screws
-pro-bond wood glue
-4' x 4' sheet of 3/4 birch plywood (many use MDF, but low Weight is VERY important in this application)
-t-nuts for mounting the sub
-bolts that complement the t-nuts
-parts express bolt style terminals

tools used:
-18v cordless skill saw
-18v cordless drill/driver
-framers triangle
router with 1/4 straight bit
4' level
tape measure
pencil (mechanical gives you a consistent line)



The First key to Success is to have a plan, even a crappy one (as shown) 










firstly I jotted down my given variables. These are values that I can not change. In this case I was limited to a 14" max height and a 28" width.

I also measured the slope of the back of my back seats. It was approximately 4" greater at the bottom near the floor then the top near the “ceiling”. I will refer to this number (4”) as my “D2” (or the difference of my bottom depth vs. my top depth) (this will make more sense if you reference Speaker Enclosure Volume Calculator and make use of their volume calculator)

This left me with my “D1“ (top depth) as my adjustable variable. I could make this length smaller or larger to hit my target airspace. I chose 5" in this case because I wanted to make the box as thin as I could and still have clearance for the woofer. Using all these numbers I calculated some basic geometry and found my interior angle of ~17.5 degrees. (The slope of the box face)

I also knew that the thickness of the wood was 3/4” keeping this in mind I had "Lowe's" cut my entire board in half upon purchasing it to 26.5 inches wide. (We will later find out that they can't cut that straight, but close enough that I could correct it with sanding)

Plans:
Length: 26.5 + .75 +.75 (for each end piece) will give me my magic width of 28”
Height: 13.25 =.75 (I planned to screw the front baffle flat to the bottom piece of the box, and to face of the top piece so I didn’t need to ad 1.5 inches, just account for the bottom)

Using the above linked calculator I will end up with a total value (before bracing) of 1.34
A good middle ground between the pg recommended .85spl and 1.65sq recommendations for my xenon 10d2 woofer.

Cutting time:

The piece if wood pictured is the piece I had “Lowes” cut (like a Home Depot if you don’t have them where you live)

It has a uniform width of 26.5” per my cutting request (more or less….grrr, they aren’t the best cutters)

This will stream line the process because now I only have to make 1 cut for each of the four pieces the will form the non-end pieces of my box.

Pro’s have table saws…..I don’t. I have a cordless skill saw so I will have to make do.

To ensure a straight cut I take a measure of the length of the piece I am about to cut and make a cute arrow










I do this on both the far left and right of the board to make sure its straight. Then using my handy level I draw the line I am about to cut. 










The saw I use has a 1” guard on it so I add 1” to my measured line, and secure my level down with clamps creating a cutting fence. This will keep my cutting line true.

From my previous calculations I move my angle setting on my saw to 17.5degrees. I do this first because the piece I cut will produce an identical angle on the end of the left over board. If you plan it properly, this will reduce the number of total cuts you will have to make. 










I will repeat this process until I have a:

top, (angled 17.5 on one end) 
front baffle (angled on both sides, complementary) 
back, (straight on both ends), 
and a bottom (also angled 17.5 on one end – 

you will notice later that it is 3 inches longer then the previous specified depth of the box, this is because I will use that 3 inches to create a buffer between the back of the seat, and the woofer cone. It will also give me space for my one-day custom grill!


Now that we (or me as it were) have Four 26.5” x X” pieces, I will start joining them. First get wood glue. second, Apply liberally










I stand the 2 pieces up on my bench (which for me is the spare plywood on top of saw-horses) to make sure that the side is flush. Once you are satisfied with the fit, Clamp the other piece you are joining and pre drill your first hole. Then drive a screw in. 










now that you have your first screw established, you can pre drill more, I only pre-drill 2 at a time to 

A: make sure that they all line up and don’t move as I tighten down the board, and 

B: allow my bit to cool down between holes. Results may very for you, but this is what has worked for me. Not very quick, but it’s accurate.

After I joined the back, top and bottom (since the front is angled on both edges I save it for last) I decided it was high time for some bracing. Some left over scraps worked good for this, I cut them to fit snuggly between 3 of the sides and glued and screwed in place

front:










screw placement from back,












Now I have the back, top, and bottom joined, and stabilized with braces, so now I will prepare my front baffle.

Breaking out my tape measure again I find the middle of the face (and take into account that both sides are complementary sloped)

From this point you can use a compass to draw a circle and cut it out, but I happen to have a circle jig that bolts to my router, and it whoops ass.


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## bfowler (Nov 25, 2009)

Continued:

It has measured holes (the jig is face down in the picture, so you cant see the numbers) so all you have to do is pre drill a hole in the center of your front baffle, and drop a pin (nail) through the correct hole measurement, and start cutting. The only fault of this process is that the router and guide are secured to the piece you are cutting out…..which means as you finish your circle, the guide will be free to move, and that is bad. To solve this I secure the circle with clamps when I have only a couple inches left so that I can finish the circle with no movement of the guide. 











After you are done cutting you are left with a hopefully perfect hole for your sub. Now is a good time to test fit it. 










I took the rubber gasket off of my xenon sub, and it fit perfect, no movement, and it wasn’t sitting on top of the hole. Next I rotated the sub to be straight and used a sharpie to mark the holes. 










I drilled out the traced holes and fitted the t-nuts into them. To tighten them all the way, I used the largest washer I could find that fit onto the bolt. I then used my cordless drill to tighten the bolt and pull the t-nut into the hole until the spikes were set, and then removed the bolt. 


Now it is time to attach the front baffle, but first I want to brace it. 

You can see from the pics how I used some left over scrap that was already cut to the complementary angles and recessed the width of one sheet of plywood so that I would match up when I fastened it down. 




















I attached the braces with glue and screws coming from the front side. (you can see the screws slightly protruding from the back, but its inside the box so i dont mind) 










(You can also see that I took that picture before I installed the t nuts ) 

this pic shows a side view of the front baffle secured on and the bracing lining up with the existing pieces 











To create the end pieces I placed the box end up onto my remaining wood and used it as a stencil. Theoretically I should have been able to just draw the end piece and cut it out based on measurements, but by using the stencil method I can correct and potential errors that might have slipped by me. Because I had been attaching the pieces all along end up, the right side was perfectly flush. The left side however reviled that the lowe's cut was not straight and I had to sand 2 corners down to get the end to sit flush before attaching.


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## bfowler (Nov 25, 2009)

continued again....i can only include 10 pics per post

the terminals i bought from Parts express, and are pretty cool, they are a straight bolt that goes all the way though, so you don't effect the structural integrity of the box. just drill a hole and screw the terminal through 



















Next, i mount the sub and i am done!


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## philmarchand (Dec 3, 2009)

great pictures !


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## cubdenno (Nov 10, 2007)

Nice tutorial. I am a screw and glue man myself.


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## Canadian_Dude (Feb 4, 2009)

Another good way to press in t-nuts or hurricane nuts is with a c-clamp, it is less likely to spin the t-nut.

I usually use MDF and I always have trouble screwing into the edges, even with pre-drilling, so I stopped that, wood glue and clamps are more than strong enough.

Good tools are also so much nicer to work with. I have a cheap circular saw and I hate it. The guard is a dumb size, it moves, and is not accurate at all.

Great tutorial, pictures are great, and it's easy to follow.


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## Sychotic (Dec 4, 2009)

tnx very helpful


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## jorgegarcia (Mar 8, 2008)

I have problems locating MDF, where I live only a handful of mayor stores carry it and only sell it in bulk. So seeing another person using plywood helps a lot on the planning of my sub box/amp rack idea. Thanks for the tutorial, gave me a lot of ideas. bookmarked.


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## miphonematt (Sep 21, 2009)

Very cool tutorial. I'll be building another enclosure soon, and I will definitely be using some of your concepts. Thanks man!


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## JVCS80T6 (Dec 23, 2009)

Very nice, I built a similar box and was trying to figure out why you built the excess on the front in and my only guess was that is was there to keep things in the trunk from hitting the sub or so you you could do some plexi or something. Care to elaborate on the design you chose for the box?


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## bfowler (Nov 25, 2009)

thanks! the plan was to place a ring in the center about a inch in front of the sub and stretch fleece between that and the extra endges around the box to create a smooth concaved taper down to the sub.

i never got that far though


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## leorbolato (Apr 26, 2009)

Nice job


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## BoostedNihilist (Mar 3, 2008)

I would isolate the speaker terminals from the wood... the ambient moisture can be accepted into the wood creating a short between the speaker terminals.


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## Austin (Mar 12, 2009)

BoostedNihilist said:


> I would isolate the speaker terminals from the wood... the ambient moisture can be accepted into the wood creating a short between the speaker terminals.


How would you isolate them? Coat them in something?


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## newtitan (Mar 7, 2005)

wow VERY good idea on the routing clamp method

never once thought of that

you learn something new everyday!!!!


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## Dr. MERINO (Oct 2, 2008)

Hi colleagues, Happy New Year, excellent tutorial on the procedure to build your box, it looks very good,
. saludos desde mexico


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## BoostedNihilist (Mar 3, 2008)

to isolate the terminals, cut a hole with a holesaw and use a plastic plate over the hole... or a terminal cup.


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## mas penk (Jan 9, 2010)

does the material have any effect on sound quality.. I mean if you some heavier material (like MDF) then the sound will be better than if you use regular plywood (same thickness)??


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## danielp (Jan 6, 2010)

I think its not the Thickness but the Stiffness of the material. The less Flex on a box the better it is..


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## Austin (Mar 12, 2009)

danielp said:


> I think its not the Thickness but the Stiffness of the material. The less Flex on a box the better it is..


Also the density of the wood. ( Medium Density Fiberwood MDF)


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## danielp (Jan 6, 2010)

Totally agree with you. 

Can a less Dense board be used but sealed and stiffened properly?


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## Austin (Mar 12, 2009)

danielp said:


> Totally agree with you.
> 
> Can a less Dense board be used but sealed and stiffened properly?


Sure. The sealing part isn't the hard part, it's making it not flex, resonate and the like. You can try searching for "sound deadener on sub box" or variants of that. There have been a few threads I've seen where they talk about it.


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## danielp (Jan 6, 2010)

Awesome.. Thanks for the advice.


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## bfowler (Nov 25, 2009)

BoostedNihilist said:


> I would isolate the speaker terminals from the wood... the ambient moisture can be accepted into the wood creating a short between the speaker terminals.



i know that makes sense in theory, but i have never even heard of that happening. have you seen that happen before?


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## bigguy (Apr 13, 2010)

thank you for making this, It helpd when i made mine, all thought i could not manage to mesaure wothr anything and my box is ugly.


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## jasondplacetobe (Jun 15, 2009)

where did you get that pissa little circle cutter for the router?


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## bigguy (Apr 13, 2010)

jasondplacetobe said:


> where did you get that pissa little circle cutter for the router?


Search "jasper jig"


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## bfowler (Nov 25, 2009)

yup, jasper jig. i got mine from partsexpress.com. they go on sale periodicly


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## Mako312 (May 10, 2010)

Thanks for this. I need to learn how to build boxes.


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## Deluca119 (Jul 7, 2010)

Thank you, this is very informative!


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## elsporko (Jul 16, 2010)

Thanks for the instruction. The one part (even though its a small one) that kept me from spending the $40 in parts to build my own box instead of $60 to buy one was the little "terminal cup" or whatever they use on the retail ones. Those jacks look like a much better solution; i'd rather use as little plastic as possible.


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## Cruzer (Jul 16, 2010)

wish pics were there, worth 1000 words. while ive built a few boxes, always nice to get more ideas and better ways


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## bendow (Aug 5, 2010)

cool..thanks! I'm going to need this!


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## bfowler (Nov 25, 2009)

i just realized all the pics on this are broken now. i will fix those tonight


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## Cruzer (Jul 16, 2010)

bfowler said:


> i just realized all the pics on this are broken now. i will fix those tonight


much appreciated


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## jamaldonado (Apr 10, 2011)

Any fixes on the pix, would like to check them out.


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## bfowler (Nov 25, 2009)

im not allowed to edit the old posts apparently to fix the pics. so heres the link to the origonal thread:

Phoenix Gold Phorum • View topic - Bfowler's Big Bad Box Building Butorial, er, I mean Tutorial


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