A new approach to time-scale expansion of short-duration complex acoustic signals is introduced. Using a subband signal representation, channel phases are selected to preserve a desired time-scaled temporal envelope. The phase representation is derived from locations of events that occur within filter bank outputs. A frame-based generalization of the method imposes phase consistency across consecutive synthesis frames. The method is applied to synthetic and actual complex acoustic signals consisting of closely spaced rapidly damped sine wave. Time-frequency resolution limitations are discussed.