1. A method of analyzing a multichannel audio signal, said method comprising: for each of a plurality of frequency components of a segment in time of the multichannel audio signal, calculating a corresponding indication of a direction of arrival; based on the calculated direction indications, selecting a subset of the plurality of frequency components; based on the selected subset and on a plurality of basis functions for decomposing the audio signal, calculating a vector of activation coefficients, wherein each activation coefficient of the vector corresponds to a different basis function of the plurality of basis functions; and reconstructing at least a selected portion of the audio signal based on the vector of activation coefficients.