What is the term for the quietest sound that can be detected by the human ear?

The term that refers to the quietest sound that can be detected by the human ear is known as the "Threshold of Hearing." This concept is critical in the study of sound and human perception, as it represents the minimum intensity of sound that can be perceived by an average human without any other noise. At this threshold, sound waves have a certain pressure level, typically around 0 decibels (dB), which is a reference point in acoustic measurements.

Understanding the Threshold of Hearing provides insight into human auditory capabilities and is foundational in fields such as audiology and sound engineering. Other options, while related to sound and hearing, refer to different concepts. The Threshold of Pain indicates the intensity level at which sound becomes painful, the Sound Barrier refers to the speed of sound and the challenges associated with surpassing it, and Decibel Level pertains to the measurement of sound intensity in a logarithmic scale rather than identifying the quietest sound detectable. Each of these terms serves a specific purpose within the study of sound but does not define the quietest perceivable sound like the Threshold of Hearing does.