Drums are percussion instruments with a membrane or "skin" stretched tightly over a hollow body. They can be played with sticks, mallets or hands. When a player strikes a drum, the hand or stick pushes the skin down. This starts the skin vibrating, going up and down many times per second. This vibration pushes the air, creating sound waves.
Drum Size and Shape
The shape and size of the drum profoundly affects the sound. If a drum has a large head, it will make a lower-pitched sound. The drum head will take longer to spring back, resulting in a slower vibration, which the ear hears as a lower sound. The shape of the drum body also affects the tone. A large body on a drum will absorb higher frequency sounds while amplifying lower frequencies. This creates a warmer, more muted tone. A drum with a smaller body will have a sharper, brighter tone.
Drum Head and Attack
Most drums have adjustable heads. When they are pulled tighter, they make a higher pitch, much like a guitar string. The material the drum skin is made out of also affects the pitch. Thinner skins carry high frequency sounds better than thicker ones, while thinner skins are used for warmer, lower tones. The way the drum is played also affects the tone. If you hit a drum with your open hand or a wooden stick, you will get a sharp attack, like the sound you get clapping your hands. This attack will be followed by the sound of the drum vibrating. If, on the other hand, you play the drum with a padded mallet, you will start it vibrating without the attack. Orchestral drums use this effect sometimes to create a sound like building thunder in the distance.