This was way back in middle school when I first started to get into electronics, I created a working loudspeaker out of 2 Styrofoam plates, a coil, and a magnet. I ran it through a OP-amp and to my computer speakers. It actually didn't sound too bad. It just wasn't very loud. That is expected though considering the coil's power usage and that a 9 volt was powering it.
Text and Images © 2015 Frank Magazu.