Final answer:
Direct modifications of loudness can be achieved by adjusting the amplitude and frequency of a sound wave.
Step-by-step explanation:
Direct modifications of loudness can be achieved by adjusting the amplitude and frequency of a sound wave. A direct modification of loudness would involve changing these properties without any external factors affecting it.
For example, one possible direct modification of loudness is increasing the amplitude of a sound wave. As amplitude increases, the loudness of the sound also increases. Similarly, changing the frequency of a sound wave can directly modify loudness. Lowering the frequency can make the sound appear louder, while raising the frequency can make it appear softer.