Almost the whole world uses spruce wood to make violin panels, as long as it has a clear and hard texture and good acoustic performance. Its sound transmission speed can reach over 5116 meters per second, which is 14 times faster than the conduction speed in air. It also has a damping effect on high frequencies above 3000-5000 hertz, and has strong damping on uncoordinated high-order harmonics, making the sound clear and bright.

Moreover, the panel is the most critical sound producing component on the violin body. If the texture is too hard, it is not conducive to vibration. If it is too soft, it will result in weak vibration and prevent the violin from producing loud and beautiful sounds.

For panels, the straightness of wood fibers is extremely important. When making arches, it can reduce the probability of being cut, giving the panel more complete long fibers. The width of tree rings and the ratio of spring and autumn wood directly affect the hardness and elasticity of the panel material.

It is best for the wood grain on the panel to be between 1 millimeter and 2 millimeters each. Wood grains that are too narrow or too wide, or adjacent wood grains with large variations, are not suitable.

The panels are all made of spliced boards, in order to make the materials on the high and low frequencies more symmetrical, and to promote uniform strength and elasticity of the piano board. The sound produced by each string is balanced and harmonious, and the tone is relatively consistent.

A very important point here is that when assembling, the direction of the wood grain at the middle seam must be more parallel to the joint seam, otherwise there will be radiating wood grain at the middle seam of the assembled wooden board, and the cross-section of the wood grain will be at the middle seam, which not only affects the appearance, but also increases the wood fiber cut at the middle seam of the two boards.

The area near the middle seam is the acoustic center of the panel and also the place where the arch bears the pressure exerted by the piano code. Any defects here have a significant impact on the acoustic effect of the violin and the deformation of the arch over time.