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July 6, 2020

How to use a Vocoder | Vance Powell




One of the many advantages of working with Vance Powell as a producer is that he knows so many creative studio techniques. He’s always coming up with ideas, both big and small, to improve the sound of existing parts or create new ones. You’ll see an example of one of these techniques in this excerpt from Start to Finish: Vance Powell - Episode 9 - Vocal Editing And Background Vocals. In it, Vance takes the lead vocal track and runs it through a vocoder several times to create a cool texture to layer underneath the choruses.

Singing Synth

We pick up the action in the control room with band member Jeff Gorman sitting in front of a Korg MicroKorg keyboard, which is a compact synth with a built-in vocoder. It comes with a microphone attached on a gooseneck, which allows you to sing into the vocoder.

Jeff Gorman plays the chords to the chorus into the MicroKorg creating synth like pads from his lead vocal track.

Before discussing what Vance ends up recording, let’s talk a little about vocoders and how they work. As we know them today, vocoders, both hardware- and software-based, are used in music production to create robotic-sounding vocal parts and more.

A vocoder requires two different signals to work: The modulator (which is usually a sung or spoken voice, but can also be an instrument, even a percussion instrument) and the carrier, which is usually a synth sound—either an external one or one generated in the vocoder. The vocoder essentially morphs the modulator onto the carrier sound. As a result, you get the characteristics of the modulator superimposed onto the carrier’s audio. With a voice used as a modulator, the result sounds like a talking synth or robot voice.

If the carrier is a single-note melody, you’ll get a single note result from the vocoder. For thicker and richer results, it’s useful to have the carrier playing chords.

Triple-Layer Vocals

Back to the excerpt, Vance has Jeff test out how the vocoder setting they’ve dialed in on the MicroKorg by singing into the built-in mic. Once he’s got the sound he’s looking for, he uses the lead vocal track as the modulator and has Jeff playing the chords of the chorus into the keyboard—controlling the carrier sound. 

Vance records the vocoded copy of the lead vocal on the choruses to a new track in Pro Tools. He then records another pass with Jeff playing the chords up an octave (which changes the results from the vocoder) and eventually records a third layer.

Vance uses several effects on the aux bus for the vocoder tracks, including this Valhalla FreqEcho.

Now that he’s recorded the vocoder tracks, Vance wants to sweeten the sound—add some “schmaltz” as he puts it. He routes the three layers of vocoded audio through an aux bus and starts adding effects on the return channel.

The first one is a free plug-in from Valhalla called Valhalla FreqEcho, which is a frequency shifting delay, that’s available free from the Valhalla website. Vance sets it with a short delay of 25ms and with a relatively small frequency shift frequency of 39Hz.

He uses a Softube Summit Audio TLA Level Amp plug-in (based on an LA-2A but with some cool extra features) for compression, with a fast attack and release, and the Gain Reduction just under halfway up. For the final effect, he uses another Valhalla plug-in, Vintage Verb, which emulates hardware reverbs from the 1970s and 1980s.

Powell compresses the vocoder bus with a Softube Summit Audio TLA Level Amp plug-in.

He selects a hall setting with a 1.92 decay time. Not an overly long reverb, but with enough decay time to add the perception of a large space. You can hear the effects pretty clearly when he solos the vocoder tracks. In the end, the vocoded vocals add a lush layer of sound under the chorus.

Check it Out

Some vocoder plug-ins, such as Waves Morphoder, are designed as processors that you insert on a channel. Others apply their vocoding as software instruments. The examples in this article feature the Logic Pro X EVOC 20, which is the latter. You set it up on a MIDI instrument track and it functions as the carrier. You can bring the modulator in via the sidechain. What’s cool about the EVOC 20’s architecture is that you can play the vocoded sound via a MIDI controller or MIDI track, to match the harmonic or melodic structure.

EVOC 20, one of the instruments included in Logic Pro X, lets you combine vocal tracks with its internal synth sounds to create vocoder effects.

Example 1: If you want to go for the robot voice effect, use a single note pattern in your carrier. Here, EVOC 20 is the carrier and the modulator is a spoken voice track. The MIDI note is transposed starting at measure 5.

Example 2: The same voice track acting as the modulator, but this time the carrier track has chords playing, and at bar 5, bass, drum and keyboard tracks come in to give a flavor of a vocoded vocal within an instrument track.

The MIDI on the carrier track determines the melodic or harmonic structure. So even if your modulator is a sung voice, you can play the MIDI part to make it fit any key.

Example 3: Here’s an example with a guitar instead of the voice as the modulator playing the same chords as in Example 2. It’s a wah guitar part, which is reasonably expressive. You want a modulator with expressivity, otherwise, you’ll be missing out on an important part of the vocoder sound.