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<br /> <br />P. 01/01 WIlD <br /> <br />OSlergaard' <br /> <br />Figure 2.2 shows the relationship between sound pressure in pascals and <br />the sound pressure level indB re 20 ~Pa. It, as well as Figure 2.1, illustrates <br />the advantage of Using the decibel notation rather than the wide range of <br />pre: .'.__ ...t.:..... ...... <!oO"\I1nti l"U'pc;,:;ure is <br /> <br />dOL Post-lr F"" Nots ,a <br />cha 7671 19 <br />To <br />L. <br /> <br />Directivity f <br />degree to whic <br />direction rn.thel <br />factors for rad <br />surrounding a.s <br />pattern is actua <br />of the area of a <br /> <br />mei <br /> c. Co. <br />1 <br />the <br />A-' Fa><. F.. , <br />del <br /> <br /> <br /> <br />,15 <br />he <br />in <br />or <br /> <br />Forfee.-ride <br />Figure 2.3A. T <br />following e"an <br />observert rl reIT <br />2.3B), where th <br />at ground Jevel <br />r would be ,wic <br />will be 3 dB gre' <br />red uced by a f <br />intersection of I <br />sOUrc:e radiates <br />the area has be, <br /> <br />on~ IIou.._ in <br />Table J.l, (Soe below in E;..mpJo 2.2.) These weighting, represent adjUst- <br />ments applied to the measured SPLs in each frequency band. Note that the <br />low frequencies are markedly reduced in importance. <br /> <br />SOUND PAESSUAE' LeVEL <br />de, 'Ill 20 JlP. <br /> <br />SOUNO F'RESSVFlE (Pa) <br /> <br />120 <br />PNSUMATlC CHIPPEFllaI1.5 m) <br /> <br />'0 <br />fa <br />. <br /> <br />DIRECT< <br /> <br />TEXTILE 1.00... <br />NEWSPAPER PRESS <br /> <br />110 <br /> <br />ROCK.N.AOl.L BANb <br /> <br />OlESEI. TFlUCK 4'0 IT'Iph (., 15 m) <br /> <br />90 <br /> <br />POWER LA,WN MOWEFt (al Dper.lo,'s earl <br /> <br /> <br />fCO <br /> <br />, <br />1 <br />a,5 <br />0_. <br />0,1 <br />0,05 <br />O,~ <br />(1,01 <br />D.005 <br />O.OCJi! <br />0.001 <br />C1.DD05 <br />0,0002 <br />0.0001 <br />0.0000$ <br />0,??oo, <br /> <br /> <br />60 <br /> <br />MIL.L1NG MACHINE" (at 1.25 m) <br />GAJ<l8AGE OISP'OSA,l (ar 1 I'M' <br /> <br />PASSENGER CAR SO mph (at 1S mJ <br />CONVERSATION (Ill T,.,) <br /> <br />'0 <br /> <br />VACUUM CLEANER <br /> <br />80 <br /> <br />AIR C:ONDITIONING WrNOOlN UNf.,.. <br />(ar ~.$ m) <br /> <br />(AI SPHE <br />Q01 <br /> <br />50 <br /> <br />QUIET ROOM" <br /> <br />40 <br /> <br />30 <br /> <br />20 <br />10 <br /> <br />o <br /> <br />Figure 2.2 - FlelaUonshlp belween sound pressure le'elln decibel. (dB) <br />and Sound pressure in Pa (N/m'j. <br /> <br />ICI 11< SP~ <br />Q.::.d <br />Figure 2., <br /> <br />24 <br />