Clarinet Harmonics

Excerpt from “Interval Work on the Twelfth” from Scales and Harmonic Studies for the Intermediate Clarinetist (EHM Publishing, Nora Shaffer © 2017) 

Often, early clarinet lessons introduce new notes with a large (and important) emphasis on fingerings. Unlike our Brass cousins, this introduction often occurs without much discussion as to how fingerings relate to pitch, or even how clarinet acoustics actually work! Because of this, I think many young clarinetists develop a compartmentalized view of pitch which contributes to uneven tone and tuning. Proper study of the clarinet’s unique acoustics can resolve this issue and clarify finger/pitch confusion.

When held up to a light, a crystal prism creates a complete rainbow of color out of seeming nothingness. In fact, that “nothingness” is comprised of all of the colors. Likewise, a small pebble dropped into a still pool of water creates many ring-shaped waves beyond the initial splash. Sound behaves in much the same way. The initial tone produced by an instrument is comprised of many other pitches that are not all immediately perceivable to the human ear. These pitches comprise the harmonic series.

The clarinet acoustic only uses the odd numbered harmonics.

As you can see, the clarinet’s sequence of the overtone series is missing quite a few notes! Much of this is determined by the shape of the bore (the hollow space inside) of your instrument. Most instrument bores are conical in shape (oboes, saxophones, french horns, etc), which allow them to “overblow” at the octave. However, the clarinet’s bore is closed-cylindrical in shape, which causes the instrument to “overblow” at the twelfth. This is the reason why the chalumeau C fingering becomes a clarion G when you add the register key! Once you understand the physics behind that leap, suddenly the register change becomes much easier.