Building Your Own Drivers?

students asks: "I want to cheaply demonstrate how speaker 'drivers' (the part that makes the noise, not software...also known as a cone) work, not to produce ideal sound. Some quick research has made it clear that it's easy to find directions on how to build a fancy speaker box, but not much on how to make a driver. Unfortunately, I can't use Sake. I also can't get the thin wood. Does anyone know how to build a driver out of home materials?"

Comments

You just need some hard drives

[n1ywb]

http://www.andrew.cmu.edu/~hsakr/hdspeakers/hdspea kers.htm

Sure. Here you go.

[FreeLinux]

Here are the instructions you need to make a speaker.

Build your own driver

[Cthefuture]

Hmmm, there really isn't much to a driver. It's basically just a coil of wire attached to a suspended structure (the cone) that sits inside a permanent magnet. The energy is fed to the coil which makes it move inside the magnet which in turn moves the cone structure to create air pressure waves (sound).

Simple science-type experiments are super easy to do. No more complex than an electric motor experiment.

Although I haven't read it, this probably has everything you need.

Pictures say a 1000 words

[sweede]

http://www.silcom.com/~aludwig/images/driver.gif

You will have to create your own motor (magnet + former), your own cone and your own suspension (spider and suround)

get a few donut shaped magnets amd glue them together, a paper tube wrap some thin magnet wire around it secure it with epoxy. get a hunk of round steel and a thin plate. attach the steel to the center of the plate, put the magenets around the pole peice and attach to the plate. add another steel plate to the top with a hole big enough that the former fits in.
thats your motor

make a spider from something. get a paper cone and attach it to the spider to the former to the surround to the frame. and your done !

Or, you can get a cheap $10 speaker from partsexpress.com and use that as an example with good drawings

EASY!

[arfonrg]

Get a thin peice of steel sheet metal (thinner the better) and mount it close (closer the better) to an electro-magnet (a coil of wire) but not touching.

That's a simple speaker and how many of the really cheap ear-phones work.

Here's an example...

[arfonrg]

http://users.ev1.net/~arfonrg/SimpleSpeaker.jpg

9th and 10th grade science lesson

[Mercenary_56]

Here is a science lesson (meant for high school students) on how to make a speaker. You can download the doc here or use Google's cache here.

Building drivers is easy...

[xoran99]

./configure
make
make install

Someone had to do it :P

Better lesson - use old speaker

[eggoeater]

I use to run a pro-sound company and we would usually have blown drivers laying around. If I wanted to show someone how a driver works, I would take a blown driver, cut the surround and spider, take it apart, point to the different parts (cone, magnet, coil) and explain the theory. Then I'd take a good speaker and give a demonstration, starting with the fact that a constant current (i.e. DC) creates a magnetic field that pushes the cone in or out depending on the polarity. This is easily done with a 9v battery. (BE CAREFUL! If you do this with some cheap-o home or car speaker you could blow it!) When you apply the 9v battery to the driver, you can see the cone move up or down and it's easy to visualize the magnetic field being generated by the coil pushing or pulling on the magnet.
Next I take a cheap sine wave generator (you can get kits that cost $10) and set the frequency to maybe 5Hz (you can find cheap multi-meters that measure Hz). The point here isn't to listen (you can't) but to see the cone moving in and out. This helps the student see that the signal going to a speaker is alternating current (AC) and it quickly moves the speaker back and forth. Higher frequencies move the cone so little or so fast that it's difficult for the student to understand what's happening. So starting with a low frequency and then turning up the frequency helps the student see exactly why the speaker is making sound. The bigger the speaker the better this demonstration works. I usually had 15" drivers to mess with and you can really see the cone move at frequencies below 20.
Have fun.