Time-Scale modifications of speech signals, based on frequency-domain techniques are hampered by an important artifact called phasiness. This artifact corresponds to the destruction of the shape of the original signal, i.e. the de-synchronisation between the phases of frequency components. This paper describes an algorithm that preserves the shape invariance of speech signals in the context of the phase vocoder. At ICASSP'2001 we presented a first version of this work where phases were corrected at the onsets of the voiced portions of the speech signals. In this study, we extended the previous work by allowing the algorithm to synchronize and correct the phases at regular intervals of the voiced segments of speech signals. Due to our algorithm, modified signals, even for large expansion factors, are of high quality and almost exempt of phasiness. A demonstration is proposed at the web page: http://www.loria.fr/\~jdm/PhaseVocoder/index.html where several audio files can be down-loaded.