Читать книгу Engineering Acoustics - Malcolm J. Crocker - Страница 155

From Figure 4.8 the loudness indices, S, given in column 3 of Table 4.1 are found.

We obtain that S_max = 26.5 and ∑S = 134.2. Thus from Eq. (4.2) the loudness is: S = 26.5 + 0.3 (134.2 − 26.5) = 59 sones (OD, Octave Diffuse) and from Eq. (4.1), or Figure 4.7, the loudness level is: P = 99 phons (OD).

Table 4.1 Octave band levels of factory noise and Stevens' loudness indices.

Octave band center frequency, Hz	Octave band level, dB	Band loudness index S
31.5	75	3.0
63	79	6.2
125	82	10.5
250	85	15.3
500	85	18.7
1000	87	26.5
2000	82	23.0
4000	75	17.5
8000	68	13.5

Figure 4.8 Contours of equal loudness index.

There are several other aspects of loudness which we have not had room to discuss in this book, e.g. impulsive noise, and monaural and binaural loudness. Readers will find these well covered in Kryter's book [16].