The intensity of a sound describes its loudness at a particular distance
Sound intensity is factored by the ear's sensitivity to the particular frequencies contained in a sound
Sound loudness describes the strength of the ear's perception of a sound.
These two points being said, if the ear is more sensitive to a frequency, that sound will be louder to us than sounds at different frequencies that might not be as sensitive to our ears. So, the more intense the sound, the louder it is ;)
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