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Wind-turbine noise emission and its environmental impact are considerable issues nowadays. The purpose of this study was to identify the sound emission pattern and sound characteristics of wind turbines on the largest wind farm of Iran. In order to prepare the daytime sound level (Ld) noise map, environmental noise measurement was done based on measuring LAeq10 min three times a day according to the ISO9612 method. On the basis of IEC 61400-11.2006, sound characteristics and wind speed were measured simultaneously at the back and front of the wind turbines using TES-1358 Sound Level Meter and vane anemometer. Finally, data were analyzed using SPSS 16. The average daytime sound level (Ld) of wind farm was 63dBA which is 3 dB higher than the recommended level. Wind speed had a significant non-linear relationship with wind turbines noise up to 17 m/s approximately (P<0.001). Frequency analysis showed that the wind turbine noise is more in the low frequencies (below 1000 Hz). The wind turbine's noise was affected by the power and blade length of wind turbines (P<0.05).Sound pressure levels(SPL) in frequencies lower than 250 Hz are equal at the back and front of the wind turbines, however in higher frequencies, it is averagely 2dBA more on the back of the turbines. The blades of Manjil wind turbines rotate with approximately maximum power at high wind speeds. Hence, aerodynamic noise is higher than recommendation level; wind turbines noise is also sensitive to structural characteristic, wind speed, fluctuation and low frequency. [ABSTRACT FROM AUTHOR]