Percussion Instruments and Sound Production

Percussion instruments are perhaps the easiest to visualize in terms of sound production.  You can in many cases actually see the vibrations occur, as when you strike a snare drum or tympani with a stick or mallet.  If you look closely, you can actually see the drum head shake slightly as it vibrates. 

Percussion instruments are split into two categories:  pitched and unpitched instruments.  Pitched percussion instruments such as the steel drum or xylophones can play a melody.  Unpitched percussion such as the claves or the drums cannot play different pitches, although they can play at different dynamic levels.  An exception to this is the tympani, which has a special pedal the musician plays that can raise and lower the pitch.