Do you need to press keys obtain a sound?

Yes, in order to obtain a sound from a musical instrument, you need to press the keys. Each key corresponds to a specific note or pitch. When you press a key, it activates a mechanical or electrical mechanism that produces the sound. For example, in a piano, pressing a key causes a hammer to strike a string, producing a sound. In an electronic keyboard, pressing a key sends an electrical signal to a synthesizer, which generates the sound.