Each piano from a piano manufacturer may look similar, but to professional piano manufacturers, there might be a subtle difference—a mere variation in the piano's shell. These insiders can discern the noticeable changes. Although the system is relatively simple in its structural principles, it forms the foundation of the piano and has strong decorative functions, which is why both customers and manufacturers pay close attention to it.

1. Material Selection for the Piano Case. The piano case is closely related to furniture manufacturing. In the 18th century, pianos were used by the nobility, so cases were mostly made from precious woods, which were expensive, scarce, and served only a few. Later, hardboard was used to create cases with simple lines and styles. By the 20th century, they were made from plywood, which was lightweight, sturdy, non-warped, but costly. Modern piano manufacturers in Germany, Japan, South Korea, the United States, and other countries primarily use particleboard and medium-density fiberboard, which offer high flatness, strong impact resistance, and do not crack. These are applications of scientific and technological achievements in wood processing.

2. Shell Coating. The primary purpose of the shell coating is to protect wood from warping, yet its decorative function often garners more attention. Currently, both international and domestic coatings generally use the same unsaturated resin coatings, which are known for their high hardness and consistent durability. The drawback is their weak impact resistance. Matte finishes are often applied with polyurethane spray, offering a soft luster and are more popular in Europe and the United States.

3. Enclosure Function. The primary function of the enclosure is to install and protect the components. The two side panels of the enclosure are bonded to the wooden frame of the piano to bear the weight of the frame, side panels, keyboard, and hammers. The largest door and door panel primarily serve as a barrier and decorative element, and do not bear much weight.

4. The impact of the shell on the piano's acoustic quality is negligible. The grand piano's lid can be opened at different angles to adjust the volume and tone. Specifically, opening the lid at a 45-degree angle increases volume, making the tone bright; a 30-degree angle is used for accompaniment, with slightly lower volume and a softer tone; closing the lid reduces volume and produces a softer tone, often used for practice.