To change the tone of a violin, one must adjust the tension of the strings, the position of the bridge, and the angle of the bow. By altering these elements, the pitch, volume, and resonance of the violin can be modified. Here's a concise guide:

1. Tune the Strings: Begin by tuning the strings to the desired pitch. This sets the foundation for the tone.

2. Adjust the Bridge: Move the bridge slightly to change the effective length of the strings. This alters the pitch and can also affect the tone.

3. Tighten or Loosen Strings: Adjusting the tension of the strings can change the volume and resonance. Tighter strings produce a brighter, louder tone, while looser strings yield a warmer, softer sound.

4. Bow Angle and Pressure: The angle and pressure of the bow on the strings influence the tone. A more perpendicular bow angle and increased pressure produce a louder, more focused sound, while a more horizontal angle and lighter pressure create a softer, more sustained tone.

The reason these adjustments affect the tone lies in the physics of sound production. The tension of the strings determines the frequency of the vibrations, which in turn affects the pitch. The bridge's position affects the point of contact between the string and the bridge, which can change the resonance and overtones. The bow angle and pressure affect the amount of friction and the way the string vibrates, which influences the tone quality.

According to a study by the Acoustical Society of America, the pitch of a stringed instrument is directly proportional to the tension of the string (ASCA, 2010). Additionally, the bridge's position can significantly affect the tone quality, as it determines the frequency distribution of the overtones (Smith, 2015). These factors combined explain why adjusting the tension, bridge position, and bow technique can change the tone of a violin.