JAVS Spring 2022

Feature Article

The Three Laws of Sound Production by Cameron Reacke

One of the most important things to learn about playing the viola is how to control the quality of sound the in strument produces. Most of the expressive nuances of our performance in any piece has to do with the way that we sculpt the sound with the bow, and so developing an un derstanding of how this is done is crucial for our growth as musicians. There are three main aspects of our bow technique that we can manipulate to alter the sound we’re producing: the weight, the speed, and the contact point. The interrelationships between these three variables are complex, and there are many ways we can change them independently of one another to create different sound qualities. To help people understand how the weight, speed, and contact point relate to one another and to the quality of the sound, I’ve distilled these relationships into three simple laws: the Three Laws of Sound Production. Understanding the principles embedded in the Three Laws will guide players who are working on developing their control over sound production. To visualize these Laws, I will use “sound charts,” which are simple graphs displaying bow weight W (i.e., the force exerted on the string by the bow) on the vertical axis and bow speed S on the horizontal axis. We can draw a point—called a “sound point”—in the sound chart to show any combination of bow weight and speed that we like, as shown in Figures 1 and 2.

I will continue adding details to the sound charts as we progress through the Three Laws. The first two Laws deal with how the weight and speed relate to the produced sound, while the Third Law incorporates the contact point. All three Laws make use of something called the proportionality symbol . To those unfamiliar: don't worry. For our purposes, it only means that if the value of one side of the equation increases, so does the value of the other side—and if one decreases, so does the other.

The First Law: L WS

The First Law concerns the loudness of the sound, represented by L. This equation translates to: “the loudness of the sound is proportional to the product of the weight and speed of the bow.” In normal speech: if you add either more weight or more speed to

Figure 3: the area of the shaded triangle represents the loudness of the sound.

the bow (i.e., use a heavier or faster bow), the sound gets louder. Inversely, playing with either a lighter or a slower bow makes the sound softer. In practice, the weight and speed are often increased or decreased together to change the loudness of the sound.

On the sound chart, we can draw a straight line from the origin to the sound point. The area under that line represents the loudness of the sound (Figures 3, 4, and 5).

Figure 1: a sounding point showing high bow speed and low bow weight (a fast, light bow).

Figure 2: a sounding point showing low bow speed and high bow weight (a slow, heavy bow).

Journal of the American Viola Society / Vol. 38, No. 1, Spring 2022

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