Vocoder Backing Vocals

Tom May 24, 2021

Hey producer!

There are many techniques to use in creating a great mix. One of the hidden gems is to use a Vocoder to create ‘backing vocal’ parts. Especially in the modern Pop, Hip Hop & RnB genres.

So, what is a Vocoder?
Simply, it’s short for VOice EnCODER. It encodes the characteristics of the voice using a bank of narrow-band filters. The more filters you use, the cleaner the effect. Fewer filters used create a more pronounced synthetic ‘artificial/robotic’ quality. How does it work? The Vocoder works by breaking up an analysis signal into narrow frequency bands. The analysis signal is whatever you are using to sidechain the Vocoder. In the video, Bronwen from www.rapponline.net is using the lead vocal part from a track from the RETRO Sample Pack by 2 Deep as the analysis signal.

The included Synthesizer is broken up into the same, corresponding narrow frequency bands. So why does this make it sound like the Synthesizer is singing? First a little terminology: Envelope. The envelope is a form of automation built into synthesizers to control the value of a parameter (typically the volume or filter cut-off frequency) over time. Attack, Decay, Sustain, and Release (also known as ADSR) are the four basic parameters found on a basic synthesizer envelope generator.

And now, a very basic explanation of how we form words is needed: A human voice produces a number of resonant peaks called Formants. These Formants all occupy a really narrow frequency band, & the different human vowel sounds are created when a group of these formants combine. As we speak or sing, the formants also change as we change vowels. A Vocoder then captures the changing envelopes (see terminology explanation above) of these Formants with their really narrow Frequency bands, and the Envelope Followers apply those envelopes to the synth sound, making the synth ‘produce vowels’, as if it were ‘speaking’ the words of the vocal signal.

If the synth part is playing chords or playing notes, it will seem as if it’s ‘singing’ those words; and there you have it, the “singing synth”! All right, the sound you get is definitely “synthetic” But hey, it’s cool! All of these aspects can be tweaked with the various controls in a Vocoder, so you can dial in a ‘clear’ or more ‘synthetic’, or even ‘aggressive’ effect. Yikes, if that is all a little too technical, then just check out the video and easy steps below to working with a Vocoder in Logic Pro X!

Here are the steps to get the classic Vocoder effect with Logic Pro X EVOC 20 PolySynth.

Create a new Software instrument track
Insert the Vocoder onto the new track
On the Vocoder synth track; play in or paste some chords from a part of your song or even some melody notes you want the Vocoder synth to play back
Use the preset menu on the Logic Pro X EVOC 20 PolySynth to choose a ‘sound’ from. Eg: Vocal heaven Pad from the 02 Vintage Vocoder menu option
Route the track you want (eg: the lead vocal track in the video) to the EVOC’s Sidechain input.
Now play. Tweak and adjust to suit your mix.

There are many useful effects and wonderful sonic effects you can come up with the Vocoder.
In the modern RnB, Pop and Hip-Hop Genres, this is a really useful and must have production technique. Imagine it? Now do it!

The r-loops team.