THE SCIENCE AND APPLICATIONS OF ACOUSTICS - H. H. Arnold ...

3.11 Root-Mean-Square Sound Pressure and the Decibel 47Table 3.2. One-Third Octave Band.Lower Band Limit Center Frequency Upper Band Limitf L (Hz) f C (Hz) f U (Hz)18.0 20 24.422.4 a 25 28.028.0 31.5 a 35.535.5 40 45 a45 a 50 5656 63 a 7171 80 90 a90 a 100 112112 125 a 140140 160 180 a180 a 200 224224 250 a 280280 315 355 a355 a 400 450450 500 a 560560 630 710 a710 a 800 900900 1,000 a 1,1201,120 1,250 1,400 a1,400 a 1,600 1,8001,800 2,000 a 2,2402,240 2,500 2,800 a2,800 a 3,150 3,5503,550 4,000 a 4,5004,500 5,000 5,600 a5,600 a 6,300 7,1007,100 8,000 a 9,0009,000 10,000 11,200 a11,200 a 12,500 14,00014,000 16,000 a 18,00018,000 20,000 22,400 aa Octave marking points.While one-third octave bands generally suffice in providing adequate information,there are cases where one-tenth and even one-hundredth octaves are applied.For 1/nth octaves, successive center frequencies are related as follows:f n+1 = 2 1/n f n (3.19)3.11 Root-Mean-Square Sound Pressure and the DecibelSound consists of small positive pressure disturbances (compression) and negativepressure disturbances (rarefaction) measured as deviations from the equilibriumor quiescent pressure value. The mean-pressure deviation from equilibrium is