1. A method of classifying data according to perceptual properties of the data, the method being suited for searching and sorting large databases of media entities, including music, video and image databases, the method comprising: assigning to each media entity of a plurality of media entities in a data set to at least one class, each class of said at least one class corresponding to a subset of perceptual properties pre-defined for the data set; processing each media entity of said data set to extract at least one digital signal processing characteristic for each media entity; generating a plurality of feature vectors for said plurality of media entities, wherein each vector includes said at least one class and said at least one digital signal processing characteristic; and forming a classification chain based upon said plurality of feature vectors.