Ex. E <br />again 500 Hz and above. As a result the noise output through the louvers is dominated by low <br />frequency energy. A glance at the last line in the sound power table demonstrates the presence <br />of excess bass energy dominating the DBA sound levels <br />The preponderance of low frequency energy in the generator noise emitted from the generator <br />room has an additional impact on the noise mitigation measures used by SSA to predict <br />generator noise impact on properties to the West, South and East. Because of the long <br />wavelengths in low frequency noise, sound barriers such as the corner of a building or porous <br />barriers such as a cedar fence have minimal impact on degrading the strength of the wave and <br />according low frequency adjustments to these barrier factors have to be made. <br />West <br />The sound barrier effect of the SW corner of the building also becomes negligible when low <br />-15 dB sound <br />barrier effect, the low frequencies are attenuated maybe 3 to 5 dB. These further reduce the <br />presumed mitigations to the expanding noise from the generator room to the west by at least 10 <br />dB down from 15 to 5 dB. This barrier effect reduction of 10 dB raises the noise level at the <br />61 dBA <br />west property line from 51 to . <br />South <br />58 dBA <br />To the south, no mitigating effects were imposed and the predicted remains the <br />predicted noise level. <br />East <br />nce to the east will not <br />higher frequency range. In the bass range, such a fence will produce possibly 1 dB attenuation, <br />which means the cedar fence effect is reduced by 5 dB below the SSA estimate, resulting in a <br />sound level increase to the east from 53 to 58 dBA. <br />Error with SSA: There is an additional error with the SSA report. The distance between the <br />Generator Room and the closest residential property line <br />explanation in the SSA report why the hiking trail was selected as the nearest noise sensitive <br />property, if it was selected at all. This increased distance between the noise source and noise <br />receiving property line results in an additional 5 dB attenuation due to distance for noise to the <br />53 dBA <br />east. In the present calculation, it reduces the predicted 58 dBA back down to . <br />(iv) Exhaust Pipe Analysis <br />SSA used single number descriptors to predict the exhaust noise impact on the community. A <br />careful assessment of the exhaust noise from the octave band perspective, combined with an <br />error SSA made in the reference distance for the exhaust noise level produces noise levels that <br />are 3 dBA too quiet. <br /> <br />12 <br />