1. A method, comprising: receiving a sound mixture that includes a plurality of sources; receiving a model based on isolated training data for one source of the plurality of sources, the model including a dictionary of spectral basis vectors corresponding to the one source, the isolated training data being pitch tagged such that each of the spectral basis vectors of the dictionary of spectral basis vectors has an associated pitch value; and estimating at least a pitch feature for the one source in the sound mixture based on the model, said estimating constrained according to a constraint based on temporal data.