The loudness of a sound wave depends on the amplitude of the wave, which is the maximum displacement of the wave from its rest position. When you hit a drum, the harder you hit it, the greater the amplitude of the sound wave that is produced. This is because you are imparting more energy to the drum, which causes it to vibrate more violently. The greater the amplitude, the louder the sound.
The relationship between the amplitude of a sound wave and its loudness is logarithmic, meaning that a small increase in amplitude results in a large increase in loudness. For example, if you double the amplitude of a sound wave, the sound will be perceived as being twice as loud.
In addition to the amplitude, the loudness of a sound is also affected by its frequency. In general, higher-frequency sounds are perceived as being louder than lower-frequency sounds of the same amplitude. This is why a woman's voice is typically perceived as being louder than a man's voice, even if they are speaking at the same volume.
The loudness of a sound can also be affected by the environment in which it is produced. For example, a sound wave will be perceived as being louder in a reverberant environment, such as a concert hall, than it would be in an anechoic chamber. This is because the reflections of the sound wave off the surfaces of the room create additional sound waves that add to the overall loudness of the sound.