hjˈuːmən hˈɪɹɪŋ ɪz nˌɑːt lˈɪnɪɹ wɪð lˈɛvəl tʃˈeɪndʒ, bˌʌt tˈɛndz tə pɚsˈiːv sˈɔftɚ sˈaʊndz æz hˌævɪŋ lˈɛs bˈeɪs kˈɑːntɛnt.
Human hearing is not linear with level change, but tends to perceive softer sounds as having less bass content.