Pitch Correction: How to Keep Vocals Sounding Natural

Pitch correction is an audio processing technique that adjusts the pitch of a sound source (recorded or real-time), typically to steer the sound to be more in tune with the desired key.

The amount of shifting applied can range from sub-cent adjustments to multiple semitones.

Subtle cent-level shifting is applied to iron out natural fluctuations in pitch to create a more consistent tone and rein in slight inaccuracies. The tonality of a performance can be completely restructured using larger shifts.

Before digital tools, in the old-school analog days, there wasn’t an easy method for correcting pitch. Singers would have to re-record missed notes, or engineers could tediously fiddle around with varispeed.

Today, pitch correction tools are a cornerstone of modern vocal production, empowering artists to create perfectly polished performances.

Don’t let the word “correction” deceive you into believing these are strictly functional remedies. Innovative producers pushed these tools beyond their medicinal purpose, discovering vast realms of creative textures that have become a signature characteristic of many modern genres.

How Does Pitch Correction Work?

Pitch correction software analyzes incoming audio and splits the signal into different slices. These slices overlap, so the analysis is, in a sense, re-run over and over again.

It’s these small slices of audio that are analyzed for their pitch, and later processed in order to change the pitch of the final vocal clip, based on the key and other parameters you’ve set.

Due to the interlinked nature of time and pitch, shifting also changes the timbre of a sound due to the manipulation of formants (distinct frequency bands that dictate a vocal tone). This results in voices sounding chipmunk-esque if pitched up, or muffled if pitched down.

Tools like Waves Tune Real-Time and Vocal Bender have been developed to counteract the unwanted distortion during pitch shifting – although some producers prefer to use these artifacts as an intentional preference.

Why is Natural Pitch Correction Important?

As explained above, there’s a whole spectrum of pitch correction; from subtle tweaks to unrecognizable transformations. But why might we want to achieve a subtle pitch shifting that is likely to remain undetected to the average listener? More established styles of music, such as soul or rock, have evolved without the technology that is required to alter the pitch of vocals, so applying the technique in a brash manner would stick out like a sore thumb.

At the same time, as a species, we humans enjoy sounds that are in harmony with one another. Even non-musicians are able to detect melodic dissonance, and we tend not to find the sound too pleasing. This means that from time to time, we may need to take matters into our own hands and correct the odd off-note with the help of some choice production tools. Other times, you may need to shift the entire recording up or down in pitch in order to work with a new key.

How to Achieve Natural Vocal Pitch Correction

So, how can we avoid robotic, glitchy vocal pitch correction, and do it more naturally?

Start with a Good Recording

You may have heard people say about the production process, that you can’t simply “fix it in the mix”. While that is true to some extent, there are of course mixing tricks that can help to disguise or even completely fix recording or production issues. The same concept applies to applying pitch correction to vocals. In an ideal world, you wouldn’t have to apply any correction to your recordings, but as you’re reading this article, we’ll assume that’s not the case. At the very least, you should be aiming to work with vocals that need minimal pitch correction, such as this vocal take.

If something needs more extreme pitch repairs, you might get better results by going back to the vocal booth. Similarly, you should also be working with clean recordings that are free of any background noise, plosives and breaths. While this is a general rule, it’s particularly important when applying pitch correction, as your plugin may get thrown off by unwanted excess noise.

Let’s use Waves DeBreath to tackle the slight breathiness in our vocal recording:

Accurately Identify Your Target Key

We now need to identify which key our nice clean vocal recording is in so that we can correctly instruct our pitch correction plugin. You may already know the key of your vocal if the song’s been written already. If not, though, an efficient and reliable way to accomplish this is with a little help from Key Detector. Simply place Key Detector on your vocal channel and press play. The plugin will analyze the audio, and will quickly suggest its likely key. In this case, our vocal is in D minor.

Now, if we place Waves Tune Real-Time on the vocal channel and hit Transmit Key in Key Detector, Tune Real-Time will automatically apply the appropriate scale settings for our vocal.

Anchor Your Vocal’s Key

It can be difficult to detect iffy tuning when listening to a vocal in isolation. If you’re applying vocal tuning within a song’s entire project, remember to regularly listen to the vocal track alongside another melodic element. This gives you a reference point for you to confirm the pitch correction you’re applying is getting the vocal closer to its actual target. After all, the most important thing is how it sounds.

If you’re applying vocal repitching in a separate project, simply grab a piece of audio in the same key, or create some suitable MIDI. In this case, a simple arpeggiated piano in the scale of D Minor gives us a good reference point.

Adjust Correction Timing

Now Tune Real-Time is set up with the appropriate scale target, we can begin to adjust the parameters to achieve the desired effect. In its default state, the Note Transition value is set to 120ms, which triggers the pitch correction too slowly for this application due to some of the vocal delivery being relatively fast. For slower performances with lots of sustained and legato notes, this Note Transition time would be more suitable.

At the other end of the spectrum, if we adjust the Note Transition down to around 20ms we can hear audible pitch quantization as the plugin works to correct the pitch too quickly.

Increasing the Note Transition time to around 45ms gives us a happy medium, whereby the vocal’s pitch is corrected, but not so quickly that it sounds unnatural.

We can now repeat this step with the Speed control; reducing it until it sounds unnatural, then increasing it slightly.

Adjust Vibrato

As standard, Waves Tune Real-Time will correct any notes that deviate from the selected scale. On the whole, that’s what we’re trying to achieve here. But what about when the vocal performance contains some deliberate pitch movement that we want to retain in the recording?

Using Tune Real-Time’s Vibrato function, we can allow a certain amount of pitch modulation, whether that’s vibrato in the vocals, or glissando-style slides between notes. At 0%, the plugin will completely quantize the vocal to the chosen scale, so Vibrato mode is essentially off. At 100%, the plugin will let all pitch modulation through, and values above 100% emphasize the pitch modulation. In our example, a value of around 75% controls the pitch modulation slightly, but doesn’t lock it completely to the scale. The result gives a pitch-corrected natural-sounding vocal.

‘Mult’ Your Vocal Recording

As you can probably hear, there are a couple of sections towards the end of the recording that still sound a little out of tune. Our options are to apply more extreme pitch correction to the entire recording, which then runs the risk of making other sections of the performance sound unnatural. Alternatively, we could automate some of the parameters to work harder at the end of the recording, but with many parameters to adjust, this might be a convoluted way to tackle this. Finally, we could split or ‘mult’ the recording onto multiple channels, each with their own instance of Tune Real-Time set up with their own dedicated settings.

To do this, we’ve split the vocal at a zero point in the waveform, and moved the particularly troublesome section onto its own channel, copying the first instance of Tune Real-Time and placing it on the new channel. We can now open up the second instance of the plugin and adjust accordingly. In this case, reducing the Speed and Note Transition times, thus making it faster, gets us closer to the level of pitch correction that we need. We’ve also reduced the Vibrato amount so that any movement in pitch is a little more controlled.

Fine-Tune with Cents and Time Tolerance

While the faster Speed and Note Transition values have improved the pitch correction of the second section of our recording, it has introduced some slight quantization artifacts which are preventing the vocal from sounding as natural as it can. To counter this, Tune Real-Time features two Tolerance controls; one for Cents and one for Time.

When a target scale has been selected within the plugin, by default, it will correct the signal’s pitch when it detects audio that is at least 50 cents out of tune in either direction. We can increase this amount by adjusting the Cents in the Tolerance section. This has the effect of increasing the pitch threshold at which the pitch correction is triggered, thus softening or taming the pitch correction itself. By adjusting the additional Cents Tolerance to around 15ms, we can successfully control some of the unwanted pitch quantization that was audible before.

Not every vocal you ever work with is going to require pitch correction, and as mentioned, if a vocal needs to be completely transformed, it’s probably worth recording it again. For scenarios where some correction is required, the techniques outlined in this article will help you to do so in a subtle and natural way. If you want to see for yourself how easy it is to correct vocal pitch using Waves Tune Real-Time, you can find out more and download the free trial here.

Creative Uses for Pitch Correction

Pitch correction can be used both as a technical remedial tool, but it also presents many exciting possibilities and a colorful, creative effect.

In the last couple of decades, heavily pitched vocals have become a somewhat signature sound in a range of genres. Pioneering producers have taken this “fixing” tool and used it to create new vocal styles.

Here are some creative uses for pitch correction tools:

Hard-Tuned Vocal

Arguably the most recognizable creative pitch shifting effect, hard tuning involves applying an aggressive amount of pitch correction with fast transition times and pitch clamping to create a distinctly digital and robotic sound. This isn’t about being subtle; it’s about using pitch correction as a colorful tonal effect.

You can easily recreate this sound with Waves Tune Real-Time.

Hard-tuned vocals are common in genres like hip-hop, trap, R&B, and modern pop, where artists like T-Pain, Cher, and Daft Punk have pioneered this distinct vocal sound.

This effect is basically achieved by cranking all the controls to max on the pitcher, tightly locking the vocals to the desired notes with snappy transitions.

Building Harmonies and Layers

With tools like Waves Harmony, a single vocal performance can be duplicated and shifted to build layered harmonies. This creates expansive, shimmering, choir-esque vocal tones to add interest and dynamics to a performance.

Layering is particularly effective when the shifted layers are panned and processed with additional effects like reverb to design massive, rich harmonic vocal textures.

Resynthesis and MIDI

The concept of pitch shifting has been pushed into unique creative realms with resynthesis tools like Waves OVox. You can break down a vocal into MIDI notes and carrier signals, which in turn trigger synthesized sounds, enabling a huge range of experimental sound design.

This powerful technique augments vocals with synced instruments, essentially turning your voice into a control signal.

Layered Processing & Sound Design

Pairing shifted signals with other layered processed sounds opens up a wide range of sound design experiments.

For example, you can duplicate a vocal, add a completely wet reverb, and then pitch shift the reverb signal for interesting harmonic textures. Pitch shifters interact with other processors, both on the input and output.

When Pitch Correction Helps (and When It Hurts)

With great power comes great responsibility; you must be cautious when wielding the mighty transformational capabilities of pitch correction tools. There are just as many crippling effects as there are useful ones.

Knowing when to use a pitch correction plugin is equally important as knowing how to use them.

When Pitch Correction Is Helpful

• Fixing Nearly Perfect Performances - Sometimes, you might capture the perfect performance with the ideal energy and vibe, but there might be a few wonky notes. Pitch correction can help you to transparently repair that magical take without needing to re-record.
• Perfecting Double-Tracked Vocals - Many artists record multiple layers of vocal performance to create exotic harmonies, but small tuning differences between the lead and additional vocals can create blurring issues. Pitch correction can be used to tighten up additional vocal layers to perfectly lock with the main vocal for a cleaner sound.
• Creating a Professional Sound - The organic nature of the human body means vocals are inevitably unstable, even if to a barely perceivable level. The most skilled singers still benefit from some subtle, transparent pitch correction to achieve a completely perfect sound. There is a level of commercial standards that is now subconsciously expected by listeners.

When Pitch Correction Is Dangerous

• Flattening the Emotion - The innate fluidity and idiosyncratic nuances of the human voice are essential for conveying the emotion of a performance. Clumsy pitch correction can squeeze the life out of vocals, leaving them artificial and lifeless. Sometimes raw emotion is more important than precision.
• Artifacts and Phasing - Applying pitch correction to recordings containing background noise or prominent room sounds can create artifacts and glitchy warbling. Correction is much more effective on clean, dry recordings.
• Timing and Intonation - Pitch correction isn’t a blanket solution for fixing vocals. They can exaggerate issues that aren’t related to pitch, like bad timing, bad breath control, and sloppy articulation. Some things need to be fixed with editing, comping takes, or re-recording.

Recommended Pitch Correction Plugins

You’ll find a wide variety in the functionality and specialisation of pitch correction plugins. The best pitch correction plugin for one situation might be useless in another.

Engineers and producers often own a diverse collection of pitch correction plugins to cover the varying tasks.

The following plugins cover a broad spectrum of pitch-shifting tasks:

Waves Tune Real-Time

Designed for real-time, live pitch correction, this plugin has zero latency and is more suited for controlling vocals in the moment, rather than detailed post-processing. It’s typically used by vocalists as they capture their recordings, so they can hear the tuning in real time.

Waves Harmony

Harmony is a creative vocal processing tool that lets you create complex layered harmonies with ease. It has a range of modes to suit the needs of producers, songwriters, and engineers. It isn’t designed for precise correction, but it is the perfect tool for colorful, creative vocal processing. The low-latency processing, paired with MIDI control, makes it ideal for use in live performances.

Vocal Bender

Vocal Bender is a streamlined, real-time pitch manipulation plugin built to create noticeable hard-tuning shifting effects. It packs in a bunch of modulation effects for expression, and a mix control for layering the raw and tuned signals.

Waves OVox

OVox pushes the boundaries of what can be achieved in vocal sound design. The Organic ReSynthesis technology uses vocals to control an eight-voice synthesizer, enabling you to completely transform your voice into almost any synth sound, from vocoders to expansive pads.

Waves Tune

Waves Tune is built for precise, surgical pitch correction. Featuring a detailed piano roll and a range of editing tools, this plugin gives you full control over the minutiae of a performance. It’s an ideal tool if you need transparent pitch editing to fix certain notes.

Frequently Asked Questions (FAQs)

How Much Pitch Correction Is Too Much?

It really depends on the genre, song, and artistic vision. For traditional clean vocals, you want the pitch correction to be so transparent that you don’t even notice it.

In other situations, you might want to crank the correction parameters to max for a noticeable hard-tuned sound, like T-Pain.

What Is the Difference Between Pitch Correction vs. Auto-Tune?

Sometimes these terms are confused as different things, but technically, they are the same. Auto-Tune is a brand name trademarked by Antares, but it’s essentially just a pitch correction tool. Because it was the first to gain mainstream notoriety, “auto-tune” has been associated as a generic term, when in fact it’s a specific product.

Does Pitch Correction Affect Vocal Timbre Naturally?

Pitch correction can affect vocal timbre depending on the settings. It all comes down to how the formant processing is managed in the plugin. Subtle shifts have minimal effect on timbre, but if you’re moving it by a few semitones, it will noticeably make the tone brighter or darker. Correction tools often have formant adjustment functionality to counteract the effects on timbre.

Can Pitch Correction Be Automated in a Mix?

Yes, pitch correction can be automated, and it’s often a wise choice to do so. Using a set-and-forget approach can lead to unnecessary shifting in performance, which can flatten the natural energy. For corrective shifting, generally, you want to automate the pitching to activate only when notes need to be fixed.

When Was Pitch Correction Invented?

Experimental, rough pitch shifting has existed since the birth of speed-variable playback devices. The Eventide H910 Harmonizer, released in 1975, was the first digital pitch-shifting hardware, and Antares Auto-Tune (1997) was the first pitch correction software plugin.

These inventions laid the foundations for modern pitching tools, and sparked the emergence of new vocal textures - notably Cher’s “Believe” which exposed the creative potential of this tech to a worldwide audience.

Conclusion

Not every vocal you ever work with is going to require pitch correction, and as mentioned, if a vocal needs to be completely transformed, it’s probably worth recording it again. For scenarios where some correction is required, the techniques outlined in this article will help you to do so in a subtle and natural way. If you want to see for yourself how easy it is to correct vocal pitch using Waves Tune Real-Time, you can find out more and download the free trial here.