What is type of device u use to analyze your regular voice into the chipmunk's voice?

my friend has a program on her MP3 player. When you record your voice into the speaker, it can change your voice into a chipmunk version. WHERE CAN I GET SOMETHING SIMILAR TO THIS???What is type of device u use to analyze your regular voice into the chipmunk's voice?
The right way to do this is to double the frequency of the audiio. Speeding up the tape will do this also, but the rate of speech also increases by 2. If you double the frequency you get the high pitched voice at the normal speech rate. Maybe the link below will be of help or try a better musical supply.What is type of device u use to analyze your regular voice into the chipmunk's voice?
you can do it yourself by recording and speeding up the track, or raising all input by X_ pitch.
Just go buy a helium balloon

money