Whether you are a fan of atonal music or prefer to stick with the more melodic side of things (I will unashamedly admit I am of the latter party), you are probably familiar with what has traditionally been known as the most famous atonal work for flute, “Density 21.5” by Edgard Varèse. It was written for solo flute, without piano accompaniment, in 1936 and revised in 1946 and remains for many flute players the introduction into 20th century atonal music.

“Density 21.5” was written by Varèse at the request of George Barrere for the commission of his Haynes platinum alloy flute. This alloy consisted of 90% platinum and 10% iridium, which together has a density of almost exactly 21.5 grams per cubic centimeter. The cost of this instrument was about $3,750 in 1935—a little over $69,000 today when adjusted for inflation. The piece’s finish in 1936 was followed by a period during which Varèse produced little music; it was, in fact, the last work of any consequence the composer wrote until after World War II.

Without delving too deeply into advanced music theory concepts, “Density 21.5” is based on two melodic ideas, one modal and one atonal. “Modal” refers to being based on a scale of some sort—even if it’s not a traditional Western scale we are used to. “Atonal” broadly refers to any music that lacks a tonic or central key. Introduced at the beginning of the piece, all of the subsequent material is generated from these two themes. Despite the inherent limitations of writing for an unaccompanied melodic instrument, Varèse explores new areas of space and time in the piece by using contrasts in register on the instrument, sometimes to the extreme. Interval cycles, which are a collection of pitches that go up by an even interval every time, are used throughout the piece, with an abundance of tritones and diminished seventh chords.

Although atonal, the piece is surprisingly structured, as documented by Varèse scholar George Perle. He says, “[the] variable relation of the basic motive of Density 21.5 to the harmonic structure of the piece, and its function in articulating and clarifying the formal design, are exactly what we would expect and take for granted in the relation between motive and background in traditional tonal music.” Simply put, the piece follows a formal structure, with the exception of some new, surprising material at the closing of the piece. Of course, there is no better way to learn about a new piece than to listen, so please enjoy this performance of Edgard Varèse’s “Density 21.5.” This performance is provided with the score visible and is performed by Lawrence Beauregard.