Anyone ever build a speaker driver?

[gafftaper]

I've got a friend who has a 7 year old son fascinated by sound equipment. He wants to learn more about how stuff works. He was thinking for his 2nd grade science project next year it would be really cool to be able to build a speaker. There's lots of stuff out there about designing and building your own enclosures. But we are talking about a 7 year old who just wants to wrap a coil around a paper cone and make it bounce up and down enough to pump some AM radio through. Anyone ever mess around with building a simple speaker driver? I would love to help this young techie out but I'm more of a lighting guy. My best idea so far is to just carefully dissect a speaker and help him put it back together. Any other ideas would be great.

[koncept]

i've only seen encolsures but a quick search turned this up
http://www.mfr-eng.com/dbt.htm

you might be able to get it from a local library, but for that price i'd consider buyiing it on amazon.com or something like that

edit:
http://www.speakerbuilding.com/

[gafftaper]

The book and website you list both look like they are focused on enclosure design, construction, and matching up crossovers to the appropriate driver. There are a lot of resources out there like this on complete speaker design.

I'm trying to help a kid who wants to understand how a driver itself works and thus I'm looking for a do it yourself driver kit. Has anyone ever tried to hot glue some construction paper, copper wire, and magnets together to actually build a driver?

[koncept]

sorry, it looked like it was on the right track

http://electronics.howstuffworks.com/speaker5.htm

[jbeutt]

Yes and it's quite easy. There's no kit I know of, although there really ought to be for kids.
The speaker I built was out of paper and cardboard, except for the magnet and coil of course.
Some keys to designing a good speaker are this:
-You need to have the speaker/coil suspended and your magnet suspended seperately
-Magnet power is exponential, so get the space between coil and magnet as small as possible, but be sure there's enough space for the coil to travel back and forth.
-Use a neodydmium magnet
-make sure magnet is placed exactly center of the coil in both directions.

That animation is a really good guide for design once you've learned how speakers work.
I didn't use a spider, dust cap or a very flexable surround, however the speaker produced extremely clear sound. I think the most important pieces are to make sure you have a clean, tight coil (the coil should only be one wire thick at any point, so this shouldn't be done hastely) that's as close as possible to the magnet (i used a paper form for the coil that I placed around the magnet to get it perfect) and to make sure everything is connected securely so that when the speaker's powered up, nothing can rattle or move that shouldn't.