Which parts of the violin directly affect the vibration that produces sound?

The f holes, sounding post, and bridge are crucial components of the violin that directly impact the vibration necessary for sound production. The f holes allow the sound waves to escape from the body of the violin, enabling the resonant sound to be projected outward. The bridge serves as a critical connecting point between the strings and the body of the violin; it transmits the vibrations from the strings to the body, leading to amplification of sound. The sounding post, positioned inside the violin, assists in transferring vibrations from the top plate of the violin to the back plate, further enhancing the instrument's overall sound quality and projection. Together, these parts create an effective system for producing and amplifying the distinctive sound of the violin.

In contrast, other components listed either do not interact directly with the vibrating elements that generate sound or are not primarily responsible for sound production.