Equal loudness curves any good numerical approximation equations?

1. What do equal loudness curves show?
2. How are equal loudness contours measured?
3. What is equal loudness principle?

What do equal loudness curves show?

Equal loudness curves indicate that our perception of frequencies changes based on playback volume, at least for pure-tones. How this translates to real-world sounds and music is not entirely understood. Nonetheless, this points to the importance of mixing and mastering at calibrated volume levels.

How are equal loudness contours measured?

An equal-loudness contour is a measure of sound pressure level, over the frequency spectrum, for which a listener perceives a constant loudness when presented with pure steady tones. The unit of measurement for loudness levels is the phon and is arrived at by reference to equal-loudness contours.

What is equal loudness principle?

Equal-loudness contours describe the apparent loudness of a sound in relation to its frequency for human listeners. This scale is important because human loudness perception is extremely sensitive to differences in frequency.