Volume: The fortepiano is a predecessor to the modern piano, and it was designed to produce a softer sound than the harpsichord. The grand piano, on the other hand, is designed to produce a louder, more powerful sound.
Action: The fortepiano uses a hammer action, which means that when the key is pressed, a hammer strikes the string. This produces a louder, more sustained sound than the harpsichord, which uses a plucking action. The grand piano also uses a hammer action, but the hammers are larger and heavier, which produces a louder, more powerful sound.
Size and shape: The fortepiano is typically smaller than the grand piano, and it has a rectangular shape. The grand piano, on the other hand, is larger and has a triangular shape.
Cost: The fortepiano is typically less expensive than the grand piano.
Overall, the fortepiano and the grand piano are both beautiful instruments, but they have different strengths and weaknesses. The fortepiano is ideal for playing quiet, intimate music, while the grand piano is ideal for playing loud, powerful music.