The Vocoder:

Some of the first usages of the vocoder were for actual voice encoding used by Bell Labs for communications purposes during WWII. Just like all analogue outboard gear started out, the vocoder in the music world (which is shortened to mean voice encoder) is either a piece of analog rack gear, or it is available in most DAW’s and packs as a virtual plug-in. It filters certain frequencies and changes the harmonic content of the signal. There is an input signal and a voltage control signal. The input signal is sent through a multiband filter that is adjustable on the face of the rackmount. When you route from Protools to the Vocoder and back to Protools, keep the harmonic emphasis fully counter clockwise. If you are using an instrument, you can adjust the level -30, -15, -0db. There are 4 levels of gain staging. In terms of creating proper gain staging for the output, you can just it at the line level, mic level, attenuate using the graphic eq, and adjust the output as well. Using a keyboard direct into the vocoder as a control signal with a vocal as the input signal is a good way to get the most emphasis out of the processing because the keyboards output is pretty consistent as compared to a guitar, where there is much dynamic change. It is possible to take 2 previously recorded signals and send them through the vocoder, using one as the control signal and the other as the input signal. All you need to do this is the correct adapters and patch cables and route accordingly. Send the tracks out of ProTools on the patch bay into the vocoder, and come out the output back into protools and record it onto a new track. If you want the effect of the processed sound and no dry signal, the setting should be turned all the way to the vocoder.