The loudness of sound is related to:

The loudness of a sound is primarily determined by its amplitude. Amplitude refers to the maximum displacement of particles in a medium from their rest position during a sound wave's vibration. A larger amplitude indicates more energetic vibrations, which the human ear perceives as a louder sound. Conversely, a smaller amplitude results in a softer sound. While loudness is a subjective perception of sound intensity, it is physically rooted in the power and energy carried by the wave, which is proportional to the square of the amplitude [2]. In contrast, frequency determines the pitch of the sound—how shrill or deep it sounds—rather than its volume. The speed of sound is a property of the medium (such as air or water) and does not dictate how loud a sound appears to a listener [2].

Sources

1. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 4: Earths Interior > Primary Waves (P-Waves) > p. 61
2. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 5: Earths Magnetic Field (Geomagnetic Field) > Why Do Sound Waves Travel Faster In A Denser Medium Whereas Light Travels Slower? > p. 64