1. A method for modifying a speech signal, the method comprising: receiving, by a formants modifier of a speech converter of a speech processing system, Mth order linear predictive coding (LPC) coefficients representative of an input speech signal; converting the Mth order LPC coefficients to Mth order line spectral pairs (LSPs), by the formants modifier; multiplying, by the formants modifier, the Mth order LSPs by a scale factor to produce scaled Mth order LSPs; removing, by the formants modifier, any pair of scaled LSP with at least one coefficient in the pair above a frequency threshold to produce a Pth order set of LSPs, where P<M; converting the Pth order set of scaled LSPs to a Pth order set of LPCs, by the formants modifier; padding the Pth order set of LPCs with M-P zeros, by the formants modifier; converting the Pth order set of LPCs padded with zeros to a second Mth order set of LSPs, by the formants modifier; processing, by the formants modifier, the second Mth order set of LSPs and at least a third set of Mth order LSPs of another frame; converting the processed LSPs to processed LPCs, by the formants modifier; and re-synthesizing speech, by an LPC synthesizer of a decoder of the speech processing system, using the processed LPCs.
1. A method for modifying a speech signal, the method comprising: receiving, by a formants modifier of a speech converter of a speech processing system, Mth order linear predictive coding (LPC) coefficients representative of an input speech signal; converting the Mth order LPC coefficients to Mth order line spectral pairs (LSPs), by the formants modifier; multiplying, by the formants modifier, the Mth order LSPs by a scale factor to produce scaled Mth order LSPs; removing, by the formants modifier, any pair of scaled LSP with at least one coefficient in the pair above a frequency threshold to produce a Pth order set of LSPs, where P<M; converting the Pth order set of scaled LSPs to a Pth order set of LPCs, by the formants modifier; padding the Pth order set of LPCs with M-P zeros, by the formants modifier; converting the Pth order set of LPCs padded with zeros to a second Mth order set of LSPs, by the formants modifier; processing, by the formants modifier, the second Mth order set of LSPs and at least a third set of Mth order LSPs of another frame; converting the processed LSPs to processed LPCs, by the formants modifier; and re-synthesizing speech, by an LPC synthesizer of a decoder of the speech processing system, using the processed LPCs. 6. The method of claim 1 , wherein the scale factor is greater than one.