Pitch and Formants

Reason: Pitch and Formant Manipulation with Neptune

The Neptune device lets you adjust the pitch and formants of audio, either recorded or live. This is similar to the infamous Auto-Tune processor.

Neptune can apply subtle pitch correction, or it can create the robot vocal effect made famous in tunes by Cher and T-Pain, among others.

Basic Pitch Correction

  1. Select an audio track with a lengthy clip of someone singing or speaking.
  2. Create a Neptune device (Create > Studio FX > Neptune Pitch Adjuster). This sets up Neptune as an insert effect for your audio track.
  3. Neptune formant adjustment switch and shift amount dial

    Turn on formant correction in Neptune by clicking the button circled below.

    (For more about formants, see below.)

  4. Choose a scale from the SCALE popup menu (currently set to “Chromatic”), and set a tonic note with the ROOT field to the left of the menu, for example...

    Neptune pitch correction scale selection

    When you play the track, Neptune conforms the pitches to the ones in the scale.

  5. To get the T-Pain robot effect, turn up the CORRECTION SPEED dial to 3 o’clock or above. This reduces the portmento time between corrected pitches to a minimum.

Customizing the Correction Pitch Grid

You’re not limited to the few scales in that popup menu.

  • Click the buttons at the bottom of the previous picture (forming one octave of a stylized keyboard). This sets different target pitches. These do not have to form a common scale.
  • If your custom scale contains only a few pitches, with large intervals in between them, adjust the CATCH ZONE SIZE slider to increase the range of pitches controlled by a single target pitch.
  • For the ultimate in control (and fun), use MIDI to specify the target pitch.
    1. Routing MIDI notes to control Neptune pitch adjustment

      Be sure that MIDI is set to control the Pitch Adjust section of Neptune by choosing the TO PITCH ADJUST checkbox.

    2. Create a sequencer track for Neptune by selecting the Neptune device and choosing the Edit > Create Track for Neptune 1 menu command.
    3. With this new track selected, play the sequence and play notes on a MIDI keyboard. When you play a note, that will override the scale pitches set in the Pitch Adjust section. You can record these notes, just as you would on any Instrument track.

Harmonizing a Vocal Track

Neptune’s Voice Synth can harmonize a monophonic vocal track.

  1. Set the MIDI destination, as seen in the previous picture, to TO VOICE SYNTH.
  2. Neptune pitched signal and voice synth volume sliders

    Turn down the PITCHED SIGNAL volume slider at the right of Neptune, leaving only the VOICE SYNTH volume slider turned up. After you understand what the Voice Synth does, you can combine the two signals.

  3. Create a sequencer track for Neptune, if you don’t already have one, by selecting the Neptune device and choosing the Edit > Create Track for Neptune 1 menu command.
  4. With this new track selected, play the sequence and play chords on a MIDI keyboard. When you play a chord, the voice in your track will sing using the pitches you hold down. You will hear sound only while you hold notes down. You can record these chords, just as you would on any Instrument track.

    Note that the Pitch Adjust, Transpose, and Formant controls do not affect the Voice Synth.

About Formants

A formant is a resonant frequency present in many acoustic sound sources, such as stringed instruments and voices. Formants are often fixed in frequency, with the frequency determined by the physical characteristics of a resonating body. For example, an acoustic guitar has some resonant frequencies that are due to the size and shape of the guitar box, and these frequencies are emphasized regardless of the pitches that you play on the instrument. Formant frequencies are partly responsible for the characteristic sound of an instrument.

Voices are similar, with the additional complication that the resonating cavity — the mouth and throat — changes shape constantly to produce different vowel sounds. Each vowel you sing has a characteristic set of formant frequencies, regardless of the pitch you sing.

When you transpose the sound of a voice or an acoustic instrument, you shift these formant frequencies by the same interval that you shift the fundamental and its overtones. This can make a voice sound unnatural: like chipmunks when you transpose higher, like a monster when you transpose lower. Essentially, this is like decreasing or increasing the size of the vocal cavity.

Neptune is capable of analyzing the formant frequencies of incoming audio and preserving these formants while the audio undergoes transposition. All you have to do to make this happen is turn the FORMANT switch on (as shown in the first picture on this page).

Neptune formant shift dial

You can also achieve creative effects, such as gender changing, by using the SHIFT knob, which shifts formant frequencies higher or lower than they were in the original sound. This happens independently of other transposition that Neptune performs.

Additional Neptune Tips

  • Use the pitch bend wheel, fed from the Neptune sequencer track, to create or enhance inflections in spoken word tracks. Adjust the bend range with the number that is above the bend wheel.
  • Use the mod. wheel, fed from the Neptune sequencer track, to add artificial vibrato, with an adjustable rate.
  • Use the Transpose feature to shift the pitch of the entire input stream by a number of semitones and/or cents.
  • If you move audio from one place to another in the sequence, and you are processing that audio using Neptune, and you are controlling Neptune from notes in a track, then you also must move the clip containing those notes so as to align with the new location of the audio.