1. A method of voice transformation using one or more processors comprising: segmenting the voice-signal into non-overlapping frames, wherein for voiced sections the frames are pitch periods; generating amplitude spectra of the said frames using Fourier analysis; transforming the said amplitude spectra into timbre vectors using orthogonal functions; manipulating the voice parameters of the said timbre vectors to generate a set of new timbre vectors according to the specifications of voice transformation; inverse transforming the new timbre vectors into new amplitude spectra using orthogonal functions; generating new phase spectra from the new amplitude spectra using Kramers-Kronig relations; generating elementary acoustic waves from the new amplitude spectra and the new phase spectra using Fourier transform; producing a new voice waveform by superposing the said elementary acoustic waves according to the timing data given by the new timbre vectors.