Tone is one of the most important features of beautiful viola or violin playing.
• A good tone, loud or soft, is ringing, almost like the sound of a voice singing. A less good tone can be thin and wispy, or harsh and scratchy.
• First, check in with the amount of tension in your shoulder, arm, wrist, hand, and fingers. Ideally this whole apparatus should be supported by your back, and feel buoyant and springy, rather than heavy or tight.
• Be sure your bow is generally moving parallel to the bridge. Experiment with your contact point--what happens when you move closer to and farther away from the bridge?
• The default position for the arm is about a centimeter above the string. At the start of a bow stroke, the hand drops into the string with the bow hair at an angle. This ensures a ringing, open sound at any volume.
• Remember that no matter what kind of sound you want to make, the more relaxed and receptive your muscles are, the more you allow vibrations to flow through your body and the instrument.