Two variables that can be adjusted to predict a buzzer’s expected performance are distance and voltage input. The equations shown here solve for SPL for either distance or voltage if the designer knows the buzzer’s rated SPL at a given drive voltage. In Example 1, the buzzer’s specs indicate that at 10cm, the SPL will be 75dBA, but the designer wants to know how loud it will be at 30cm. In Example 2, the buzzer’s specification indicates that when running the buzzer at 3V, the SPL will be 75dBA, but the designer wants to know how much louder it will be if running the buzzer at 9V. When trying to predict SPL at higher voltages, never actually run the buzzer beyond the manufacturers’ recommended operating voltage range (VOp). Doing so may permanently damage the buzzer.