This is an addition to my first instructable, it go's into much more detail about how to make the custom speaker box. This thing is a fully fiberglassed enclosure with 2 15" woofers, 5 tweeters and 1 mid range. Its powered by a deep cycle battery and is used with a dual lane 2400 watt amplifier located inside. It has a car stereo that controls the volume and the music. The backrest is covered in purple felt and lined with a rubber strip. There are 2 sets of lights on the back with a total of 50 leds each of blue and red lights with a controller box located under neath the speakers.

Step 1: First Get Supplies for Fiberglassing

Remember this is what i used for mine you have to judge how much you will need.
You will need:
Concert Speaker (Any will work)
2 Gallons of fiberglass polyester resin
6 Yards of fiberglass matting
3 yard of polyester
4 big tubs of Bondo
Particle Board
Speaker Wire
Optional:
Car Amplifier
Car Stereo
Tools I Used:
Staple Gun
Nail Gun
Reciprocating Saw
Spray on glue
Bondo Spreader
Lots of Gloves

Step 2: Make the Frame for the Design You Want

First make the frame for how you want it look, i wanted mine to be a big box for loud sound and I wanted it to look wild. Try not to make such a hard design as like I did in the middle with the odd speaker sticking out in the middle because i spent alot of hours fiberglassing and bondoing that thing.
We made the base of the speaker box a rectangle with the front two corners rounded for a nice look.
We then added that thing that looks like a shark fin, that is there for the shape and added support.
As you can see in the second photo we had to cut out a ring that would be there to make sure the 15" sub would fit. I had to use a nail and a piece of string to make the ring an approximate size. I cut it out and filed/sanded until the speaker sat it in snug. We used posts to hold the speaker ring were we want it to be in the final design. The other speakers we did the same thing by cutting out rings to fit the other speakers and had them suspended by the posts. The frames for the speakers have to be abled to hold the weight of the stretched polyester. We then added a back to the box because we wanted that to be flat. You should wire now depending on how many speakers or how much access you have to the inside of the box after.

Step 3: Drape the Polyseter Now

Now that you have the frame up and wired you can now start to stretch and staple the polyester to the box.
Now i do not have a picture of the fabric before I fiber glassed it but it basically looked the same as the pictures.
When your stapling it to the box make sure that there are no wrinkles or its gunna be more work later. Start from the top and work your way down. As you can see in the pictures we had to go and get more polyester because we didn't have enough. We had that obstacle in the top part of the speaker box we had to put polyester over it after we had finished the other two sides.

Now that you have the polyester on the frame we need to harden it to make it workable. We now had to mix the polyester resin with the catalyst. REMEMBER do no use too much catalyst, i used to much and the resin got so hot that it got burning hot started smoking and instantly hardened, and didnt smell nice either. Once you have it mixed up paint the resin onto the fabric and make sure that the fabric soaks it up well. We waited a full day and tested to see if it had dried with a mixing stick, once we knew it was dried we made another batch of resin and cut 2"x6" strips of fiberglass and started painting them on. If you can paint the fiberglass on horizontaly and when you do the next coat do it vertically. When you are doing this try to make sure there are no bubbles or clumps of fiber glass, its worth taking the time for this instead of spending twice as much time later.

We only did 3 coats of fiberglass, some people say to use up to 7 coats but we felt like it would be strong enough and it turned out it was : ).

Step 4: Start to Bondo

Now grab your bondo and your gloves and start to cover your fiberglass in bondo, we found out the best way to do it pretty much when we were done. Try to get it as smooth as you can and as thin as you can while it still covers the fiberglass. It starts setting in around 3-4 mins so you have to work pretty fast. After you have sufficiently covered the box in bondo it is time to sand, wear a mask mostly because you might start sanding the fiberglass and you cant inhale that. Sand it down to the shape you want with 150 grit. We somtimes would sand on a fiberglass bubble and would have to bondo it to make it smooth again. After you have it how you like sand it with 400 grit so its perfectly smooth.

Now you need to cut out the holes for the speakers, for the big ones i used a reciprocating saw and a file and for the little ones i used a 2 3/4 inch circular drill bit. Make sure the speakers fit before you paint.

Step 5: Paint the Box

I chose a purple and yellow theme. For the paint I used some automotive spray paint primer and some purple krylon. I did 2 coats of primer to make sure it was on the box sufficiently. I then did 3 coats of purple. You can if you want use Clear Gloss Enamel, I used 2 coats of that to protect it and give it a nice shine. Now all you have to do is install the speakers and it should be ready to go!! If you need any help or would want me to put a less complex fiberglass tutorial up please comment.