Final answer:
The human ear is most sensitive at a frequency of 4000 Hz, which aligns with the most sensitive point on the Fletcher-Munson curves. Humans can detect sounds from 20 Hz to 20,000 Hz and typically need a frequency difference of at least 1 Hz to distinguish two separate sounds. The threshold of hearing in decibels varies for different frequencies, with the most sensitive being around 4000 Hz (D).
Step-by-step explanation:
According to Fletcher and Munson, the human ear is most sensitive at a frequency of 4000 Hz. This finding is based on studies that created the Fletcher-Munson curves, which show the average sensitivity of human hearing across different frequencies. The curves clearly demonstrate that our ears are more sensitive to sounds around 4000 Hz, meaning we can hear these sounds at lower volumes compared to sounds at other frequencies.
The average human hearing range is from 20 Hz to 20,000 Hz. For an average person to distinguish two separate sounds, the frequencies must vary by a minimum of about 1 Hz when not played simultaneously. However, this ability to distinguish frequency changes can vary with the pitch; for example, it might be easier to distinguish a change of 1 Hz at lower frequencies and require slightly larger differences at higher frequencies.
The sensitivity of human hearing is also depicted by the audible thresholds in decibels for different frequencies. For instance, sounds at 4000 Hz can be heard at quite low decibels signifying high sensitivity, whereas frequencies at either end of the hearing spectrum, such as 100 Hz or 15,000 Hz, require higher decibels for audibility.