The violin sound beam, like the panel, is made of spruce wood, requiring a straight and uniform grain. The width ratio of spring and autumn wood is close to 1:1, which is more suitable. Due to different growth conditions of trees, there may be differences in material between soft and hard. The former makes the violin sound soft and dull, while the latter tends to make the sound sharp and noisy. So the softness and hardness of the material should be appropriate. Generally, violins and violas should use wood grain every millimeter, while cellos should choose wood grain every 1.5 millimeters.

Splitting the panel wood is the preferred choice. It should not only be split along the direction of the wood grain, but also in the direction perpendicular to the annual rings. This ensures the correctness of the fiber direction of the violin bass beam, making the wood fibers coherent and parallel in all directions of the beam.

After processing, when viewed from the end of the bass beam, the wood grain (annual ring) at the top thread is radial cut, which means it is parallel to the side of the bass beam and evenly arranged with consistent intervals. Splitting the top surface of the bass beam can ensure that the wood fibers align with the direction of the panel's wood fibers. Due to the curved shape of the sound beam, it is obvious that many wood fibers will be cut off. Therefore, during the processing, attention should be paid to keeping the top surface of the bass beam parallel to the plane of the panel edge as much as possible until the curved shape of the bottom surface of the beam matches well.

Afterwards, when trimming the side and top surfaces of the bass beam into the final shape, not only can the maximum amount of wood fibers be retained as coherent, minimizing vibration interference to the panel, but also reducing the probability of choking with the wood fibers when pushing the planer, making the trimming smoother and more perfect.