JAVS Spring 2022

According to the Second Law, the sound density increases when we increase the bow weight or decrease the bow speed. To make the sound airier (i.e., less dense), we decrease the weight or increase the speed. We often change both the weight and the speed at the same time to change the density of the sound. Because the density is proportional to the bow weight divided by the speed, it’s represented in the sound chart by the slope of the line drawn to the sound point. In Figures 9, 10, and 11, that line has been extended and donned an arrow to make this visually clear. The more upwardly the arrow points, the denser the sound is; and a lower-pointing arrow represents an airier sound. At the same time, we can also still see the area of the triangle representing the loudness. Looking back at Exercises 1 and 2 (and Figures 6 and 7), we’ll find that the as pect of the sound we were changing—other than its loudness—was of course its density. Figure 12 dia grams Exercise 1 and high lights the density change by including the density ar

change the weight when you do this). That’s an increase in sound density.

In Figure 13, you can see that when you perform Exercise 2, both the loudness and the density increase when you increase the weight of the bow. What you should hear— when only increasing the bow weight—is the sound getting louder, but it should also get that same tight, possibly crushed, quality it had when you decreased the speed in Exercise 1. That, again, is an increase in sound density, shown by an increase in the slope of the density arrow. Lowering the weight or increasing the speed will, of course, have the opposite effect: to decrease the density. The sound will seem to relax and have a softer edge to it.

Figure 9: the sound’s loudness and density are represented by the area of the triangle and the orientation of the arrow, respectively.

Figure 12: changing the bow speed changes both the loudness and density of the sound.

Figure 13: changing the bow weight changes both loudness and density of the sound

Figure 10: high-pointing arrow, high-density sound (a heavy, slow bow).

Now experiment with Exercise 3 again to see if you can change the density of the sound without changing its loudness. Using a slower, heavier bow, and then a faster, lighter bow in the right proportion will maintain the loudness at a constant level while changing the density. Finding that proportion is a matter of trial and error. At this point, it might have occurred to you that Exercise 3 has a complement. Exercise 4: While playing long notes, increase or decrease both the weight and speed at the same time to increase or decrease the loudness of the sound while keeping its density the same (Figure 14). Again, maintaining a constant density requires that you increase or decrease the weight and speed together in the right proportion, which you can find through practice.

Figure 11: low-pointing arrow, low-density sound (light, fast bow).

rows. The chart shows that, as we reduce the speed of the bow, the sound’s loudness decreases, and its density in creases . As the sound becomes softer when you slow down the bow, you should be able to hear that it also seems to become tighter, maybe even crushed (remember not to

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

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