Wind turbines represent an encouraging option for sustainable energy but their noise emissions can be an issue for their public acceptance. Noise reduction measures, such as trailing-edge serrations or permeable inserts, seem to offer promising results in reducing wind turbine noise levels. This manuscript presents a novel holistic approach for perception-based evaluation of wind turbine noise and the performance of reduction measures using synthetic sound auralization. To demonstrate its feasibility, a case study featuring four state-of-the-art noise reduction trailing-edge add-ons synthetically applied to two full-scale wind turbines at nominal power is presented. The synthetic sound signals were auralized and propagated to three observer locations. The expected annoyance in each case was estimated by employing a combination of psychoacoustic sound quality metrics and a listening experiment featuring 16 participants. A close relation was found between the results of the psychoacoustic metrics and the listening experiment. In general, this holistic approach provides valuable information for the design of optimal noise reduction measures and wind turbines.