Hello my name is Frank Davis. I love this project and I thought it would be interesting to share with everyone how it works and how it build it. If you have any questions when building just post them below and I will be glad to help. I know this project is nothing new and has already been done before but I think my version is a little more detailed and precise then some of the others out there. Have fun!
Step 1: Materials
Styrofoam Plate - Better resonance is the reason for choosing styrofoam, paper and plastic plates have a much duller sound. But feel free to play around with different types of materials.
Construction Paper - This is used as the coil and also to "mount" the speaker. I had previously used printer paper but found it wasn't sturdy enough for my liking.
Styrofoam Square - I just cut this out of an old styrofoam presentation board, it is used as the stand or base of the speaker. Material is not of high importance here just make sure it is sturdy as this will be supporting the entire structure, including the magnet.
Scissors - Used for cutting and shaping construction paper. Make sure you use sharp scissors to make your cuts perfect as it will directly effect the balance of your speaker (which directly effects the loudness of your speaker).
Wire - This is crucial guys! Make sure you get 32 awg enameled wire, 30 awg will not work as easily (I will explain later). The best place to get this is Ebay in my opinion because I ordered 300 feet for 5$ (free shipping). This is used as the coil.
Magnet - Again this is very important also. The strength of the magnet you choose will decipher the loudness of your speaker. I find it is much easier to use a circular magnet for this project because I can't even imagine trying to build a square voice coil. Again Ebay is the best place for magnets, I always use neodymium magnets as they are the strongest available. The magnet I choose was 20$ and has a pull force of 150lbs. So please be very careful with these magnets if you choose to use them, they will destroy or computer or laptop with no problem, and can also break fingers very easily.
Super Glue - The most useful resource on the planet. I use super glue when I don't want to wait for Elmers glue to dry but with much patience it will work just as well. Although with super glue one mistake probably means you have start over again from the beginning as it eats through Styrofoam like acid.
Elmers glue - For this entire project I am going to highly recommend using this because it just turns out much better. Remember patience is virtue.
3.5mm Jack - This is how we are going to send the speaker music. Find an old pair of headphones and strip the leads down. Also if they look greenish or redish after you strip off the plastic it may also be enameled. If that is the case you will have to find some light sandpaper or a lighter and make sure you have bare metal exposed on both leads. The one I choose was actually from an old speaker of speakers and was a Tri-conductor.
Step 2: Step 1 - Find the Center of Your Mount.[IMG]http://i249.photobucket.com/albums/gg210/Frankanthony1/Center.jpg[/IMG]
Take a ruler and draw a line from corner to corner on your styrofoam square forming an X and you should have your perfect center, super simple!
Step 3: Find the Center of the Bottom of Your Plate
For this step, I find using Thales Theorem is the easiest was to do this... as this rather challenging to explain I suggest using the step by step on this website as a reference, http://www.mathopenref.com/constcirclecenter2.html. Remember you could just guess the center and your speaker will still work but its quality will lack.
Step 4: Cut Out Your Voice Coil Base.
Measure the height (h) of your magnet as it lays flat. Cut 3 strips of construction paper about 8" x h". In my case h = 1". This will be the coil.
Step 5: Place Your Magnet
CAREFULLY place the magnet on top of a scrap piece of construction paper and trace the circle. Then use the technique from step 3, http://www.mathopenref.com/constcirclecenter2.html, to find the center of the circle, poke a hole in the center, and cut out the circle. Using a metallic pen to trace the circle may present a challenge... as the magnet might rip the pen out of your hand.
Step 6: Trace the Circle.
Trace the Circle onto the center of your "mount" and your plate. (Tip: I used a red pen to mark the center of the plate and "mount" so I could find it easier through the pin hole.)
Step 7: Assemble the Voice Coil Base.
Now Place the magnet on top of your table, preferable metal as it will help to keep the magnet stable. Grab your strips of construction paper and wrap them around the magnet individually. Wrap the 2nd over the first and the 3rd over the 2nd and tape them individually so they will stay in place. Wrap them as tightly as you can. The 3rd or outermost ring is the one we want to use so also tape the inside of it so it doesn't unwrap it self.(Tip: Keep all tape as flush as possible so it doesnt rub against the magnet while in use, which can create bad sound.) Discard 1st and 2nd ring.
Step 8: Glue the Voice Coil Base and Magnet Into Place
Be careful with the placement of the ring as it will eventually have to slide over the magnet repeatedly and if it brushes at all on the magnet it will cause bad sound. You can attempt to use super glue on this step but I suggest using Elmers glue and patience but if you decide to use super glue don't use too much because styrofoam is a weird material to use super glue with and it occasionally will eat right through it and you will have to start your plate over again. Get a light book and rest it on top until glue is dry, wait like 30 minutes or just come back tomorrow. (Tip: The taped part of the ring always seems to want to pop out and mess up the circle so when the glue is curing I put pressure towards the center on it.) Now when you are placing the magnet in the circle on the mount you really only need a dot of glue.(I do this incase I want to reuse the magnet). Make certain that you apply the magnet on a nonmetallic table top because as I said before these magnets are very mean and can mess up everything. Oh and...
Make it stick
Step 9: Wrap the Coil.
Now its time to wrap the coil, start off leaving about 12inches of wire to the side and lightly tape it to the plate, this will be one of your leads. Now continue to wrap the wire around the base of the ring. You must have at least 30 turns if you do not go around the base 30 times the coil will not magnetize and your speaker will never work. Saying that I suggest going around 40 times just to be safe, this usually results in around 7.5 ohms which is close enough. After you feel you have completed the wrapping leave another 12 inches of slack before you cut the wire and tape it next to the other lead. (Tip: lightly dripping superglue over the wire really helps to keep the coil in place.)
Step 10: Build Your Spider!
Okay I guess this is more like half spider half frame but this is what will keep your voice coil centered and supported. Now grab your construction paper and cut out two strips that are 4(h) by h (h = your Magnets flat height). For example my H = 1" so my strips are 4" tall and 1" wide.
Step 11: Form Your Spider.
This is a very crucial step guys. First take the two strips of construction paper and tape them together so that the folds will be exactly the same on each of them. Now fold it in half and then fold the halves in half towards the center (see picture).
Step 12: Mount the Spider.
Glue the folded strips of construction paper on to the plate first, use elmers glue and wait the required 27 years. Make sure that the middle fold points away from the coil and that you place each stand in the same place on each opposite side of the coil. Once that is in place slide the coil over the magnet and make the stands sit "comfortably" so that the coil sits right above the height of the magnet. You can do the bottom of the stand with super glue if it is not styrofoam, if you did it with elmers glue wait 60 years to make it stick.
Step 13: Connect the Wires.
It should kind of look like a speaker now! All you have to do its sand or burn off the enamel from our leads and solder them to the end of our 3.5mm adapter!
Step 14: Wrap Up and Video.
Now you can plug it in to your ipod or computer or dig up the old amp in your room and hook it up to that... it may start to smoke.... turn it up all of the way maybe even run some bass tests through it, its fun to watch it move up and down slowly. If the sound quality is bad check for obstructions, if it doesn't work at all make sure that you are plugged into a good source(check with headphones), then make sure you got all of the enamel off of the coil leads. Otherwise you may need to rewrap the coil with more turns. Anyway good luck and have fun I hope yours turned out well! Total elapsed time of project = 30 minutes.
Heres another video http://s249.photobucket.com/albums/gg210/Frankanthony1/?action=view¤t=speaker.mp4