A directivity pattern generator for producing sound patterns using a modal architecture is described. The directivity pattern generator may include a beam pattern mixing unit, which defines sound patterns to be emitted by an audio system in terms of a set of frequency invariant modes or modal patterns. The beam pattern mixing unit produces a set of modal gains representing the level or degree each of the predefined modal patterns is to be applied to a set of audio streams. Modal filters may be used to modal amplitudes that compensate for inefficiencies of the each modal pattern at low frequencies. The directivity pattern generator may include a modal decomposition unit for generating driving signals for each transducer in one or more loudspeaker arrays based on weighted values for the modal gains/amplitudes.