books.google.com.br - Loudness is the primary psychological correlate of intensity. When the intensity of a sound increases, loudness increases. However, there exists no simple one-to-one correspondence between loudness and intensity; loudness can be changed by modifying the frequency or the duration of the sound, or by adding...http://books.google.com.br/books/about/Loudness.html?hl=pt-BR&id=78L77CopexQC&utm_source=gb-gplus-shareLoudness
