Audacious Audio

The phenomenon of the "singing flame" has been known since the 19th century. Place electrodes either side of a flame and, if you apply a high enough audio-modulated voltage to those electrodes, the ionized particles in the flame will cause it to emit sound. (Search YouTube for "singing flame" and you'll find many examples.) This principle was developed into a practical loudspeaker in 1946 by a French inventor, Siegfried Klein, who confined an RF-modulated arc to a small quartz tube, coupled it to a horn, and called the resulting speaker the Ionophone. An intense radio-frequency electrical field ionizes the air between inner and outer electrodes to produce a distinctive, violet-tinged yellow flame in the quartz combustion chamber. When the RF field is modulated by the audio signal, this causes the almost massless ionized flame to expand and contract in what should be a perfectly pistonic manner.

There are as many ways of designing a digital-to-analog converter as there are engineers. One approach is to select parts from manufacturers' data books and build the product according to the "application notes" provided by the parts manufacturers. This is the electronic equivalent of a paint-by-numbers kit.

A more creative engineer may add a few tricks of his own to the standard brew. Bigger and better regulated power supplies, careful circuit-board layout, tweaky passive components, and attention to detail will likely make this designer's product sound better than the same basic building blocks implemented without this care. Indeed, the vast range of sonic flavors from digital processors containing very nearly the same parts attests to the designer's influence over a digital processor's sound.

There is always a conflict between the needs of reviewers and the realities of the marketplace. Once a reviewer has invested his time and energy in a review, he would like that product to remain in production for all time, which would allow it to be used as a reliable recommendation forever. But whatever the product and whatever the category, sales of a product almost always follow the same triangular curve: a sharp rise at the product's introduction, a maximum reached sometime thereafter, and then a steady decline to a sustained but low plateau. Marketing-minded manufacturers therefore introduce a new model every three or four years, in hopes of turning that single triangle into a continuous sawtooth wave.