What is the impact of higher altitude on sound perception during flight?

At higher altitudes, the atmosphere becomes less dense, which influences how sound travels. As the density decreases, the ability of sound waves to propagate diminishes, leading to a reduction in the perception of sound. In essence, because sound relies on particles in the air to transmit vibrations, fewer particles at higher altitudes result in less effective sound transmission. This diminished sound perception can make sounds seem quieter or less clear compared to those experienced at lower altitudes.

In contrast to this, sound loudness and distortion are not typically experienced to the same degree in the context of changing atmospheric density at altitude. Higher altitudes usually do not change sound frequencies significantly, nor do they amplify sound; thus, the perception of sound remaining unchanged or becoming louder is not accurate.