Method and apparatus for generating vocal harmonies

摘要

Disclosed are a method and apparatus for analyzing an input vocal signal to produce a plurality of harmony signals that are combined with the input vocal signal to produce a multivoice signal. The method makes a current estimate of the fundamental frequency of the input vocal signal and determines if the current estimate is the correct estimate of the fundamental frequency. If the current estimate is correct, a reference note is assigned to correspond to the current estimate and a plurality of harmony notes are selected to correspond to the reference note. The method then generates a plurality of harmony signals by scaling the input vocal signal with a piecewise linear approximation of a Hanning window to extract a portion of the input vocal signal and by replicating the extracted portion at a plurality of rates equal to the fundamental frequencies of each of the harmony notes. The plurality of harmony signals and the input vocal signal are combined to produce the multivoice signal. The steps of the method are carried out with a microprocessor and a signal processing circuit.