making a radio effect transform

Does anyone no how to do this? on one audio track making radio effect transforms into the orignal clean audio. I use to do this with Adobe Audition 3 and their FFT filter, but i cant find a way to do this with P.T 10. i tried EQ filters, phasers and flangers..also ive tried 2 seprate tracks 1 radio effect and one oringal track then fade one out as the other fades in but it has a wierd phase sound..any thoughts??

thanks