US 5,231,671 A · Method and apparatus for generating vocal harmonies

Abstract

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.

Claims20

Dependent claims

A method for analyzing an input vocal signal representative of a musical note in order to produce a plurality of harmony signals that are combined with the input vocal signal to produce a multivoice signal, the method comprising:

determining a previous estimate of the fundamental frequency of the input vocal signal;
determining a current estimate of the fundamental frequency of the input vocal signal;
testing the current estimate based on a set of parameters derived from the previous estimate of the fundamental frequency to determine if the current estimate is a correct estimate of the fundamental frequency;
assigning a reference note to correspond to the current estimate, if the current estimate is the correct estimate;
selecting a plurality of harmony notes based upon the reference note;
generating a plurality of harmony signals that correspond to the plurality of harmony notes;
and
combining the plurality of harmony signals with the input vocal signal to produce the multivoice signal.

5 more elements

Apparatus for analyzing an input vocal signal representative of a musical note in order to produce a plurality of harmony signals that are combined with the input vocal signal to produce a multivoice signal, comprising:

signal processing means for sampling the input vocal signal and storing the sampled input vocal signal in a digital memory;
a frequency detector for determining a current estimate of the fundamental frequency of the input vocal signal;
computing means for testing the current estimate based on a set of parameters derived from a previous estimate of the fundamental frequency of the input vocal signal and for determining if the current estimate is a correct estimate of the fundamental frequency, wherein the computing means assign a reference note corresponding to the current estimate if the current estimate is the correct estimate;
means for determining a plurality of harmony notes based upon the reference note;
means for generating the plurality of harmony signals corresponding to the plurality of harmony notes;
and
a mixer connected to receive the plurality of harmony signals and the input vocal signal in order to combine them to produce the multivoice signal.

4 more elements

Dependencies are inferred from the claim text.

Method and apparatus for generating vocal harmonies

Life of this patent

Method and apparatus for generating vocal harmonies

Life of this patent

Abstract

Claims20