Aluminum Screams: A Saltwater Synthesizer
If you touch copper wires to a drop of saltwater on aluminum you can hear decaying and regenerating synthesizer-like sounds! I stole this idea from Nyle Steiner, who I gained tons of information about thermocouples from for the last post. Mr. Steiner is the inventor of a variety of Electronic Wind Instruments and has played on a ton of TV and movie soundtracks-good movies too, like Apocalypse Now!
So, what do you do to make the aluminum scream like the metal coins did in dry ice a few posts back? I did this:
Run two copper wires to a speaker or guitar amplifier.
Join the wires together with a resistor of at least 100k value.
Touch one wire to the aluminum.
Touch either the insulation of the second wire to the aluminum with a little saltwater on it OR carefully touch the copper part of the second wire to a droplet of saltwater on the aluminum WITHOUT touching the aluminum.
You can just attach the wires to the end of a guitar cord, the other end of the cord is of course plugged into a guitar amplifier.
Soda cans are made of aluminum.
Both wires are bridged together with a resistor. Use one that's 100k or more. I tried a few different values and heard no difference, but I didn't try many put out and I had them parallel, not in series.
It seems that I got more complex sounds when touching the wire, or just the rubber insulation to corroded or damaged parts of the aluminum.
Here's a taste of the weirdness in video/audio:
...do you still hear the aluminum screaming Clarice?
So, what's going on? Well, if you hook up a multimeter you'll find aluminum plus saltwater produces voltage. The voltage is variable. So this may be like a keyboard synthesizer Voltage Control Oscillator (VCO). Saltwater on aluminum foil can be used to create an ultra simple electrolytic battery that can power an LED. Changing voltages makes noises, whether it's steel guitar strings affecting the magnetic field of the guitar's pickup, a microphone diaphragm moving because of human voice sound waves or this crazy setup.
To juice up the electrolytic aluminum and Saltwater battery you can add lye. What would that do to the sound output of our saltwater synthesizer?
Would solid core copper wire sound different? How about different concentrations of saltwater? Burned aluminum? Aluminum that's being heated or even red hot? How about lemon juice instead of saltwater?
This is a great thing to have on the shelf for future experimentation when nothing else is going on. It's simple and easy to change variables in this little circuit.
By playing around you can obtain incredibly complex noises that evolve and sound like Electronic Music. It's really, really weird.
"Build stuff-you'll have fun!" -Michael Logusz
Abstract music, abstract kitty! Meow.
