How does it affect the instruments performance?

The belly of a violin controls how the vibration/sounds resonates and is projected. 25 Meaning that a few things would be taken into account when determining to sort of sound produced. One, the curvature and two, the size of the belly itself.1, 2, 3, 25 The higher the curvature the tone produced will be soft but brighter and sweeter. 2, 3 The flatter the curvature, the harder and stronger the tone!2 Lastly the bigger the belly size (comparing a size violin to that of a sized violin) the larger the vibrations created. 25