In this instructable, I will walk you through some of my explorations in making homemade speakers, which you can then use as a jumping point for your own explorations.
-Paper Speaker Circuit (including TIP12x or MOSFET transistor -- instructions for constructing your own can be found here)
-Audio Source ( I used a sound effect gag gift, but greeting/birthday/etc. cards that have a sound component also work well )
-Conductive Materials ( I used copper tape, conductive steel thread and bare conductive ink)
-Additional materials for building forms ( paper, plastic, fabric, etc. )
-Powerful Rare Earth Magnets ( neodymium, etc. )
Step 1: Exploration 1: Flattened Copper Spiral
Starting with a conventional paper speaker design, I worked by creating a flat spiral composed of one solid piece of copper tape. Connecting both ends to the circuit and placing the magnet in the center yielded an expected (mild) sound. I also attempted to augment the sound with several sheets of paper in between the individual magnets, but there wasn't any audible difference.
Step 2: Exploration 2: Flattened Plastic Bag
Taking a plastic sandwich bag, I attempted to recreate the circuit using conductive steel thread, hopefully with the sound projected from the inside of the bag. This attempt was also audible, but seemed slightly higher in pitch than the paper, which I'm assuming to be a result of the more pliable surface of the plastic.
Step 3: Exploration 3: Conductive Ink
For the third material comparison, I decided to try using conductive ink in a similar design. However, this method did not result in anything audible. It seems the lax conductivity of the ink was unable to create a workable electromagnetic field.
Step 4: Exploration 4: Vertical Paper Spiral
For the fourth exploration, I decided to use a different setup, aligning the conductive material in tighter spirals by using it in a vertical setup across sheets of rolled up paper. The tighter spirals were expected to create a more robust sound, but this was not the case. It seems the inflexibility and amount of paper separating the copper tape was too much for the field generated.
Step 5: Exploration 5: Vertical Tape Spiral
In response to exploration 4 not working, I decided to try a more flexible material in place of paper. I used regular scotch tape this time, which did give me an audible sound.
Step 6: Exploration 6: Pill Bottle
For the 6th exploration, I decided to use a pill bottle wrapped many times with copper tape and scotch tape to separate the layers. I went through 2 iterations of this, the first containing one layer of copper tape in a spiral and the other containing 6 or 7 layers. Additionally, I tried cutting up small strips of paper to pick up more subtle vibrations. Both of these attempts yielded relatively loud results, which could be heard around 5 or 6 feet away in a moderate volume shared studio space. Surprisingly, the number of times wrapped and additional material inside the bottle made little difference to the sound.
Step 7: Additional Explorations
The final exploration I did was using the roll of copper tape itself, which was loosened up to allow the alligator clip to attach the the core of the roll. Despite the large space between the magnet and tape pieces, an audible sound was heard.
Additionally, I have provided 2 images of previous explorations. Let me know if you have any interesting explorations of your own!