I have a theory, if that's the right word, and after thinking about it, my confidence wanes.
Nevertheless, I believe that if I move a ferrous material in close proximity to a permanent magnet that has some sort of copper wire wound around it without coming into actual contact with the magnet, I believe that an electrical current will be induced in that copper wire.
Further, I believe that if I am able to change the length of, or the tension in this ferrous material, (let us suppose for the purpose of our discussion, that a wire or "string" of wire will suffice as the material I have in mind,) then I can increase the oscillation in this "string" and thereby effect a change in the frequency of the current thus induced.
Additionally, I believe that I can take this "current", if that is the term that best describes making the electrical current utile - let's put a pin in that and clean up our language later - and somehow amplify it before routing the signal to a "loud speaker", I may be able to provide a means of occupying my time, increasing my frustration, draining my bank account and filling my unoccupied storage spaces, for days, months or even years to come!
If I am correct, I may even be able to waste further time and treasure in discussing my theory in online forums!
I'll let you all know if my experiments prove fruitful. Stay tuned.