A computational model for loudspeaker arrays using the complex directivity data of point sources can predict the radiating pattern of any continuous line source. A line source of finite size can be decomposed into a set of smaller sources that can be measured and then treated as point sources that contribute to the far field. Any linearly extended loudspeaker with discrete elements can be simulated with this computational model, even more accurately when accounting for the acoustic support of adjacent cabinets. A comparison of measured and predicted performance of different arrays demonstrates the utility of this approach. Other approaches of comparable accuracy can be computationally expensive and are often of limited applicability.