This system is reported to provide better results than those using uniform scaling when issued in CALL packages, however it may present problems due to memory saturation that may difficult its use in real applications. Finally a hand-sized portable device for time-scaling modification for hearing impairment is proposed in [6],in which only the duration of those segments of signal above a certain power level are expanded, while the segments below that level remain unchanged, which corresponds mainly to consonants and semi-vowels segments.