A guitar string plucked strongly makes a loud sound. A guitar string plucked gently makes a soft sound. A drum skin hit hard makes a loud sound. A drum skin hit gently makes a soft sound.
Pitch is a term used to refer to the height or lowness of a sound. The pitch of a sound is determined by the frequency of the sound waves. A higher pitch has a higher frequency. The noted called A that is the first A above middle C is often used as a note for tuning instruments to match each other, and has the frequency of 440Hz.