Optimal and Adaptive Virtual Unidirectional Sound Source in 
                        Active Noise Control

<table>Noise N5 (power
plant turbine) attenuation. — Spectrum
with ANC, - - - spectrum without ANC.</table>

Advances in Acoustics and Vibration

Figure 16: Optimal and Adaptive Virtual Unidirectional Sound Source in 
                        Active Noise Control 