The Fletcher-Munson Curve is a graph that shows how the human ear perceives different frequencies at different sound levels. The graph is divided into two parts: the X-axis, which represents the frequency of the sound, and the Y-axis, which represents the sound level in decibels (dB).
The graph shows a series of curves or contours that represent the minimum amount of sound energy required to perceive a given frequency at a certain loudness level. These curves are known as equal loudness contours, and they represent the sound levels needed to produce the same perceived loudness for each frequency.
The Fletcher-Munson Curve graph demonstrates that the human ear is more sensitive to certain frequencies at lower sound levels, and less sensitive to the same frequencies at higher sound levels. This means that in order to achieve a balanced frequency response at different sound levels, audio engineers must adjust the frequency response of audio equipment (such as speakers or headphones) to compensate for this uneven perception of sound.
For example, at low sound levels, the ear is less sensitive to bass frequencies, while at higher sound levels, the ear becomes more sensitive to bass frequencies. Therefore, audio engineers must adjust the frequency response of audio equipment to boost bass frequencies at low sound levels, and reduce them at higher sound levels.
In summary, the Fletcher-Munson Curve graph is a visual representation of the way the human ear perceives sound at different frequencies and sound levels, and it is an important tool for audio engineers and musicians in ensuring a balanced and accurate representation of sound.