Sample-based engine noise synthesis using a harmonic synchronous overlap-and-add method

In order to synthesize the noise of internal combustion engines at arbitrary speed variations, an overlap-add-based method is proposed to be applied to sound samples extracted from a prerecorded engine noise at a continuously-varying speed. The objective of this new method is to minimize the phase discontinuities between a finite number of harmonics of the sample sounds likely to be concatenated. The harmonicity of the synthesized signal is then preserved which greatly enhances the acoustic quality of the restitution. Moreover, the synthesis stage is well suited for real time applications due to a low computational load compared to existing approaches. The proposed analysis-synthesis method can be applied to any harmonic sound whose spectral content depends solely on its fundamental frequency. By analogy to existing overlap-and-add methods, the method introduced here is referred to as Harmonic Synchronous Overlap and Add (HSOLA).