How to Use a Vocoder on Audacity

By Seamus Islwyn

Create sci-fi robot vocals with Audacity's vocoder effect.
i Brand X Pictures/Brand X Pictures/Getty Images

A vocoder combines a recording of a human voice with a synthesized waveform to produce a robot-like effect. The Audacity free, open-source audio editing program includes a vocoder plug-in that you can use to produce this effect. Audacity's vocoder requires you to create a stereo waveform with the vocal on the left channel and the synthesized sound on the right. The vocoder then modulates the left-hand channel with the right-hand one.

Step 1

Launch Audacity. Open the "File" menu and hover the mouse over "Import." Click "Audio."

Step 2

Navigate to the vocal recording to which you want to apply the Audacity vocoder. Double-click the file to load it into Audacity. Click "OK" if Audacity asks you to confirm the import method.

Step 3

Open the "Tracks" menu. Click "Stereo Track to Mono" to convert the imported audio to a mono track. Open the "Tracks" menu again, hover the mouse over "Add New" and click "Audio Track." Audacity will create a new mono audio track underneath the vocal.

Step 4

Open the "Generate" menu and select "Tone." Set the "Waveform" to "Sawtooth." Click "OK." Audacity will generate a carrier waveform for the vocoder to use.

Step 5

Click the down arrow next to the name of the vocal in the upper-left corner of the Audacity mixer window. Click "Make Stereo Track" to join the vocal and the generated tone.

Step 6

Open the "Effect" menu and scroll down to the bottom of the list of effects. Click "Vocoder" to open the vocoder plug-in.

Step 7

Adjust the "Number of Vocoder Bands" slider in the vocoder plug-in window as desired. The more bands you use, the smoother the vocal will sound; however, a high number of bands will also greatly increase the effect's processing time.

Step 8

Click "OK" to apply the vocoder effect. Click "Play" to listen to the vocoded vocal.