Applying the chirp function to a .wav file

Hi,

I was wondering if there is any way possible to apply the frequency response to any chirp signal to a .wav file. I am capable of generating the chirp with a pure cosine signal but I would like to apply this same concept to a .wav file. I used wavread and now have the sampled signal. As of now I'm using a phase vocoder and changing the pitches of segments of the signal and then playing them back as one sound, but this sounds broken as you can hear the broken segments. Any help would be greatly appreciated. Thanks in advance for any help. :)