So, you've downloaded some songs by Abney Park (one of the world's few steampunk bands) onto your Datamancer laptop or your Old Time Computers-accessorized PC ... do you just listen to them through the built-in speakers? Not if you're Polish tinkerer Conscious Flesh. He has created a speaker that not only looks delightfully mad-Victorian-scientist-esque, but it actually produces sound using plasma discharges. Nikola Tesla would definitely approve.
Ordinarily, speakers work by using a mechanical diaphragm (such as a woofer or tweeter) to move air. The Steampunk Plasma Speaker, however, heats the air using a high-frequency electric discharge. This causes the air to expand, creating pressure waves that act as sound waves. By manipulating the amount of power used to create those discharges, different sounds are made possible.
The voltage used to create the plasma discharges comes from what is known as a bottom-fed Tesla Coil (of course). One end of that coil is connected to a high-voltage, high-frequency generator, house within a vacuum tube. The discharges are contained within a sealed glass chamber, that maximizes the speaker's efficiency, while minimizing ozone production. A brass horn is connected to that chamber, which is said to improve the reproduction of lower-frequency sounds.
The video below provides a sample of the Steampunk Plasma Speaker's sound quality. Note the similarly steampunk MP3 player used for the demo.