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How does a voice pedal change the sound of your voice going through a microphone? Answered

My friend, Sue, has a voice pedal that has hundreds of voices you can use to spice the songs you sing. Her brother used it once to do 'Alvin and chipmunks' just to have a little fun. While I was sitting there listening to her I was trying to figure out how that works. Her brother doesn't have a high pitch voice, it's actually pretty deep. It's not like he put a cloth over the microphone to muffle the sound or use a different voice.


I'm not sure how it works either. Instead of a normal voice changer though, I use certain guitar pedals. I do this by having a non-powered lapel mic connected to an in-line power source [in other words a battery configuration to make it compatible with the pedal], and the pedal's output is connected to two daisy chained X-Mini II speakers. [This only works with some pedals.]

There are two ways to change sound;  one is amplitude and one it frequency.
If the frequency changes the pitch is altered.   If the amplitude is changed, volume is altered (sound pressure). Since frequency is inversely proportional  to wavelength, a higher pitched sound will have a shorter wavelength.  Raising the frequency or shortening the wavelength then, will give the Chimpmunk sound.

8 years ago

If you could record and playback a very short loop at different speeds at the same time, with speed differences of 6% per change of note, you would have a live analog pitch changer that is musically correct. It is easier to build but harder to program the same digital effect, which is not much different than autotune, I think.

It's changing the pitch. Alvin and the Chipmunks was originally done by recording at one speed and playing it back faster. That's the easiest way to change the pitch that I know of. You can still do that sort of thing with any basic sound-editing software, even windows recorder. Better sound-editing software, like the popular freeware program Audacity, can be used to alter the pitch without messing with the speed of the sound (or to retain the pitch and speed up/slow down the sound). These programs work by altering the waveform of the sound you provide. Digitally recorded sound isn't really continuous. It's actually a series of sampled tones that are taken in rapid succession, and played back in rapid succession so that it sounds like a continuous piece of audio. It's sort of like recording a film in that way (in film, you use a series of pictures that are played back rapidly enough to give the illusion of motion). This opens up the ability to apply an algorithm to the recorded sound. In this case, the computer changes the pitch of each individual sampled tone, one after another. I don't think there's an analogue circuit out there that changes pitch in live-sound. I could be wrong. I'm certain that effects like your friend's pedal or like a voice-changer toy/tool operate using a microprocessor. Just like PC software, the software in the gadgets is designed to read the sound input, alter the pitch, and spit it back in real-time.

Way back, I got a chance to see Les Paul in concert and he used his Les Paulverizer to sing like Elvis and do other cool stuff. He was at the forefront of analog digital delay and recording electronics on which a lot of the digital stuff is based on. It really is pretty amazing what people did to innovate music and recording, of course, the electric guitar bears his name.

That is an intriguing effect. Unfortunatly, I've never had such a great opportunity to see a great artist at work. I'm truly jealous. I don't know if I'll ever get to see the guy perform, it says he's 98. Its true, if there was ever a maker that could design an analogue pitch-shifter, it'd be him.