IEC Acoustic Standard IEC 61400-11
IEC Acoustic Standard IEC 61400-11
IEC Acoustic Standard IEC 61400-11
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Calculate L 70% for Classification<br />
Within each critical band every spectral line is classified<br />
as tone, masking, or neither<br />
Calculate L 70% level<br />
The energy average of the 70% of spectral lines in the<br />
critical band with the lowest spl levels<br />
L 70% = 33.13 dB A<br />
Calculate the criterion level, L 70% + 6 dB A = 39.13 dB A<br />
sound pressure level (dB A)<br />
NATIONAL RENEWABLE ENERGY LABORATORY<br />
50<br />
45<br />
40<br />
35<br />
30<br />
25<br />
20<br />
15<br />
10<br />
5<br />
0<br />
198<br />
201<br />
204<br />
207<br />
210<br />
213<br />
216<br />
219<br />
222<br />
225<br />
228<br />
231<br />
234<br />
237<br />
240<br />
243<br />
246<br />
249<br />
252<br />
255<br />
258<br />
261<br />
264<br />
267<br />
270<br />
273<br />
276<br />
279<br />
282<br />
285<br />
288<br />
291<br />
294<br />
297<br />
300<br />
frequency (Hz)<br />
Freq (Hz) spl (dB A) 10^0.1*spl<br />
198 25.30 338.67<br />
201 25.50 354.59<br />
204 26.02 399.88<br />
270 26.37 433.42<br />
273 26.79 477.90<br />
291 27.10 512.81<br />
288 27.38 546.63<br />
300 27.46 557.78<br />
276 27.61 576.47<br />
285 27.67 584.37<br />
294 27.68 586.63<br />
282 27.74 594.64<br />
267 27.78 599.23<br />
297 27.91 617.72<br />
279 28.68 737.67<br />
207 29.15 822.10<br />
261 29.38 866.01<br />
258 30.45 <strong>11</strong>08.94<br />
264 30.78 <strong>11</strong>97.30<br />
210 32.15 1642.39<br />
255 35.09 3231.56<br />
213 37.62 5781.61<br />
219 39.75 9447.28<br />
222 39.86 9678.80<br />
216 39.88 9733.16<br />
228 40.31<br />
225 41.20<br />
252 41.22<br />
237 42.31<br />
231 42.48<br />
243 43.21<br />
240 43.43<br />
246 43.50<br />
234 43.87<br />
249 45.44<br />
sum/n 2057.10<br />
10*log10 33.13
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