frequencies
f 2 = v w / 2 = v w / 2L = 2 f 1 . Similarly, f 3 = 3 f 1 , and so on. All of these frequencies can be changed by adjusting the tension in the string. The greater the tension, the greater v w is and the higher the frequencies. This observation is familiar to anyone who has ever observed a string instrument being tuned. We will see in later chapters that standing waves are crucial to many resonance phenomena, such as in sounding boxes on string instruments.