In the audio piece titled "Piano Signal Version 2", a piano serves as the primary instrument. The piece begins with a soft, tranquil melody that gradually transforms, introducing a more complex and dynamic range of notes. The transformation is marked by a shift to a higher pitch, creating a sharp yet pleasant tone that resonates throughout the piece. The piano's notes ring out clearly, each one standing out distinctly, yet all blending together in a harmonious symphony of sound. The high-pitched notes add an element of urgency and intensity, capturing the listener's attention and engaging their senses. The overall effect is a sophisticated and layered sonic experience that showcases the versatility and emotional depth of the piano.