The length of a piano does not necessarily determine its sound quality. Instead, the craftsmanship, materials used, and maintenance of the instrument are more significant factors affecting its sound. However, there is a common misconception that longer grand pianos sound better because they can produce a louder and more resonant sound due to their larger soundboard and longer string lengths. But, in reality, a well-maintained smaller piano can deliver a wonderful sound that is just as pleasing to the ear.