1. A method of producing dynamically controllable data composites from two or more data segments, the method comprising: training one or more function mappers to map between one or more feature envelopes sets that are extracted from data segments of audio data and one or more corresponding parametric representations of the audio data by using at least one training parameter to discriminate between the data segments in a training process for the one or more function mappers, the one or more feature envelope sets corresponding to one or more perceptual characteristics of the audio data, and the one or more parametric representations corresponding to one or more spectral characteristics of the audio data; forming a composite data structure by using at least one control parameter to combine values for a plurality of the data segments, each of the plurality of data segments being associated with a corresponding feature envelope set and a corresponding function mapper; and generating synthesis parameters for the composite data structure by feeding the feature envelopes sets corresponding to the composite data structure to the corresponding one or more function mappers and combining outputs of the one or more function mappers in accordance with the composite data structure, the synthesis parameters being used to drive a synthesis process.