Plate archings and tone: Room to breathe

The action of bowing a string applies forces to the bridge that cause it to rock in its own plane. When the rocking lifts the belly on the bass-bar side, it will depress a smaller area of the belly on the soundpost side, which in turn lifts an area in the back. Therefore, a slow in-plane rocking of the bridge alternately expands and contracts the volume of the body; a form of breathing action that is centred near the bass-bar side of the bridge. But that is not all. As the bridge lifts on the bass-bar side, the group of four strings increases in tension, and as the bridge drops there will be a corresponding relaxation of this tension. In this article, I will show theoretically and experimentally that this alternation in string tension applies forces within the body that cause displacements consistent with a breathing action centred in the upper and lower bouts…