When sounds drown out other sounds, it means that a louder sound makes it difficult or impossible to hear quieter sounds. This phenomenon is often referred to as masking. The physics behind this effect can be explained by several factors:
Amplitude: The amplitude of a sound wave determines its loudness. When a louder sound wave is present, it can physically displace the air particles more, resulting in a greater perception of loudness. If a sound wave has a higher amplitude than another sound wave, it can mask or drown out the quieter sound because it dominates the displacement of air particles.
Frequency: The frequency of a sound wave determines its pitch. The human auditory system is more sensitive to certain frequencies than others. When two sounds with different frequencies are present simultaneously, the louder sound can mask the quieter sound if their frequencies are close or overlap. This is because the auditory system may prioritize the dominant frequency or perceive it more strongly.
Temporal Masking: Temporal masking occurs when a loud sound inhibits the perception of a quieter sound that occurs shortly before or after it. The auditory system has a finite resolution in time, and a loud sound can essentially "mask" or obscure the perception of a softer sound if they occur close together in time.
Spatial Masking: Spatial masking occurs when a sound originating from one direction masks or obscures sounds coming from other directions. This effect can be observed, for example, in crowded environments where multiple sounds are present, and it becomes challenging to focus on a specific sound source.
Psychoacoustic Factors: Psychoacoustic factors, such as auditory attention and perception, also play a role in sound masking. Our attention can be biased towards louder or more salient sounds, making it more difficult to perceive quieter sounds in the presence of a dominant sound source.
Overall, the physics behind sound masking involve the properties of amplitude, frequency, time, and spatial characteristics of sound waves, as well as the complex mechanisms of human auditory perception and attention. These factors contribute to the phenomenon of sounds drowning out or masking other sounds.