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.

It's always good to have a reference. No matter the endeavor, references help guide us and set standards for all we do. For many hours of every day, I'm lucky to enjoy the reference of live, unamplified music. Right now, I average over 20 hours a week of rehearsals and performances of various ensembles, and four to five hours of listening to recorded music on my hi-fi. Clearly, for me, my musical reference is not the sound of my audio system, but the sound of live music created in various venues and acoustics.

Sometimes you hear a CD, things come up, you store it away and forget about it, until something compels you to take it out of the closet, give it a spin, and you kick yourself for your negligence, you realize, suddenly, belatedly, that this is a really special album. That's my story with Bob Brookmeyer's Standards (on the ArtistShare label), a pretty magnificent send-off from one of the most elegantly inventive big-band composers in jazz, released in 2011, shortly before he died at the age of 81.