Because stopped harmonics are theoretically identical to open harmonics, we must create the new fundamental string length over which the new set of nodes will arise. For this to work well you must stop the string firmly with your thumb, otherwise the harmonic will not speak clearly, if at all.
The most common form of stopped harmonic in the repertoire is the touch-fourth harmonic, perhaps due to the fact that the resultant pitch is easy to understand and predict: it sounds two octaves above the stopped pitch.
First, try some basic one-octave scales using only touch-fourth harmonics. As you shift from note to note, release a bit of the pressure on your thumb so that you can move more easily on the fingerboard, and then “sink in” to the new pitch with your thumb:
Next, try this G-major scale in broken thirds. Practice it in a variety of tempos and with different bowing patterns. Note that there are a few open harmonics along the way:
As we move up the fingerboard, the distance between the stopped pitch and the harmonic node gradually decreases, much the same as when we play octaves. The following exercise is a B-major scale on the A-string, with the shifts increasing in size. I recommend that you first use a glissando between the notes so that you can hear the pitch approaching.
Now let us work on the other types of stopped harmonics: touch-fifth, touch-third, and touch-minor-third. For an explanation of the sequence of pitches produced by these nodes, please refer back to the “Stopped Harmonics” section of the Harmonics Page.
As a general rule, touch-fifths are harder to reach, especially in lower positions, but will speak more easily than touch-fourths. The reverse is true for both species of touch-thirds. With these it helps to touch the node lightly so that very little surface area of the finger touches the string. A bow contact point closer to the bridge also helps.
Begin with this variation on the C-major scale. Each two-measure segment cycles through the nodes of a scale degree before transitioning to the next. Note that I have suggested two different fingerings – the lower one may not work in lower positions, depending on the size of your hand.
For further practice, try the Bugle Calls again, this time with stopped harmonics.
Next stop: Harmonics Trills