A Guide to Pitch Correction

Posted by James Cullen on

It’s a controversial topic in the pop music world. Some people love it, some people hate it. But whether you’re Kanye West or T-Pain, Bon Iver or Cher, you’ve heard of (and used) Autotune and pitch correction. Despite its controversy, pitch correction is arguably one of the most changed and versatile aspects of modern music production, and though it has many uses within vocal production, the average listener probably thinks of T-Pain or Cher when they hear ‘autotune’ instead of the many other and more subtle uses it has.


Well...do you believe in life after love?


What many lamens (and by that I mean non-music production type people) probably don’t realise is how much pitch correction will go into modern vocal production, even if they don’t think there has been any. This is partly because of the nature of how we listen to music. Fundamentally, a studio recording is different from a live performance. If you have a background in music performance, chances are you’ve been told countless times that if you mess up on stage, just keep going because people will either not notice, or they will forget. However, a studio recording of a song by a chart topping artist will be listened to millions of times for years and years, so mistakes don’t have the luxury of going unnoticed! This is where pitch correction comes in. 


It’s worth noting at this point that not all scenarios call for pitch correction. Many records have benefitted from a vocal performance that sounds more rough around the edges as this can often help to convey emotion or sincerity, and especially in genres such as folk or singer songwriter, an artificially pitch-altered performance could sound out of place (though you do hear it in some unusual places). However, let’s not get ahead of ourselves.


In this article we will have a look at how Pitch Correction came about, an overview of the big players in the industry, and then we'll take you through some tips on how to use pitch correction in your own productions.

The Intricacies of Vocal Production


Producing vocals is a dark art, and can take years to master. There are so many things to consider that you could spend a lifetime learning and practicing everything you can about producing vocals and you’d still have more to learn at the end of it all! 


The way a modern producer will record vocals is that they will have the performer record several takes of the song. They will do this over and over, sometimes even “tricking” the singer by telling them they are doing a warm up run through but secretly recording it. The end result is that at the end of the session, the producer will have many many different takes of the same vocal part. Then, the final vocal you hear on most pop records is an artificial creation. The producer will have gone through each and every take with a fine tooth comb, isolated the best performances of certain words or phrases, and then in a process called ‘comping’ these are added together to create the final vocal take. 


It’s a far cry from the early days of recording when everything was just done in one take onto a tape machine. When ‘punching in’ (the art of jumping into a tape recording mid way through to record over a mistake) came into the public eye, many singers were criticised for not getting it perfect the first time. Musicians are people too! 


In the days of this type of vocal production though, sure you could punch in on the tape machine to fix a timing mistake, but pitch mistakes were more of a challenge to fix. In an all analog setup, the only real option to adjust the pitch was to adjust the speed of the tape, and while it may have worked in some examples, we all know how comical that can sound if you’re adjusting the pitch by any drastic amount.


In the 1970s, a hardware unit by Eventide called the H910 Harmonizer allowed a producer to change the pitch of a sound without changing the length of it. This was revolutionary at the time, and gave a whole new way to tackle the problem of dodgy singers. Once MIDI was introduced to the equation, the level of pitch correction could be physically controlled to ensure the correction was correct.


Antares Audio Auto-Tune

 

This is the pioneer. The absolute king of the castle. In the 1990s, a company called Antares Audio revealed their Auto-Tune plug in, and it literally changed music forever. The reason for this is that it could alter and correct pitch in real time. It’s hard to appreciate how revolutionary this was, as we take Auto-Tune for granted now because we hear it all the time. But this really was the first thing of its kind.


So, how does it work?


It’s only right we give a shout out to Andy Hildebrand, the man responsible for creating Auto-Tune’s algorithms. These work by following the fundamental pitch of an incoming signal, which has to be a single monophonic voice in order for the effect to work well. This pitch is tracked, and then compared with a user-defined scale. So you could set Auto-Tune to A minor, and it would apply pitch shifting algorithms to ensure the input audio signal was corrected so that when it comes out the other end, it is perfectly in tune. Any note that is sung outside of the scale of A minor would be pitch corrected to its nearest in tune neighbour.


Another big shout is necessary, and this time to Cher. When you adjust the parameters of the pitch control algorithm, it has a drastic effect on the vocal sound. The more exact the pitch correction, the more the human inflection and character is removed from the sound. This is what creates the absolute robotic sound on Cher’s hit ‘I Believe’. 


T-Pain is another one of Auto-Tune’s pioneers, taking the effect to an almost comical level of use. His sound is so inseparable from Auto-Tune, that if you were to hear his voice without it you may not even know it was him! 


A more subtle approach.


Considering the above it’s easy to see how many people think Auto-Tune’s only function is to make T-Pain and Kanye (and a huge number of soundcloud rappers) feel like they can sing well.


But Auto-Tune can do a lot more than provide R&B artists with the tools to get that signature sound. Used moderately it can be a great tool to slightly fix and adjust vocal performances to be at the right pitch without sacrificing the human element. It is capable of giving results that are almost invisible, in the sense that if you didn’t know it had been tuned, you may not pick up on it. This is done by slowing down the correction process which allows room for the voice’s natural characteristics like vibrato to come through. As soon as a note is held by the vocalist, that is when the pitch correction is applied in full. 


It can even be used even more sparingly; with automation to adjust the speed of the correction to suit the needs of the vocal performance, or even bypassing the effect altogether until it is needed on the odd pitch wobble. So on one end of the spectrum we have robotic, inhuman sounding pitch correction which certainly has its place; it’s used as an artistic effect by the likes of Bon Iver or Francis & the Lights. On the other end though, we have the subtler use of Auto-Tune as a simple pitch correction tool; another piece of gear in the producer’s arsenal to ensure a faultless record at the end of the process.

This is where a large part of the controversy comes in, as some music purists believe using Auto-Tune is cheating, and they certainly don’t like it being used as a creative instrument. But as with all things, some revolutionary tools are scary to a certain number of people when they are first introduced, but Auto-tune is one of those that made its mark and is here to stay!

 

Correcting the Pitch Corrector

So, Auto-Tune was a revolutionary piece of gear, and changed the music production landscape forever. But it wasn’t without its drawbacks. One of these is its trademark sound; some people may want that level of correction without sounding like T-Pain, another is the artefacts when a note is corrected too drastically or quickly. The correction rate is also a set rate, which means if different amounts of correction are required at different times, you’d have to split up your performance across several tracks, which is obviously very inconvenient.


Considering these limitations, it’s no surprise that before long other companies were making clones of Auto-Tune. There are so many that now, even Logic Pro comes bundled with its own basic pitch correction plug in. However another huge player on the scene is Celemony’s Melodyne.


Melodyne is famous for its almost forensic level of detail that you can get into. The notes of a phrase are shown on a piano-roll like interface, so you can see in an easily referenceable way how close to the target note your vocal performance is. 


As with Auto-Tune, Melodyne can be used subtly; you can change the note’s average pitch, as well as duration, vibrato depth and starting positions of words and phrases. The level of control over these means you can adjust things slightly to get a more cleaned up sound, or you can go overboard and abuse the controls until you have something that sounds wholly unnatural. 


Melodyne even has a multitrack mode which allows you to create artificial harmonies which can sound great on a chorus! 


In general, the two plug ins are seen as two sides of the same coin. Where Auto-Tune is seen as a great tool for on the fly real time correction; a quick fix, Melodyne is seen as the more intricate forensic option, allowing much more details and finesse. The trade off then is that it is very time consuming and requires someone who really knows what they’re doing, whereas with Auto-Tune, you’re pretty much in a plug in and play situation, allowing anyone to sing ‘in tune’. Just check out soundcloud’s overabundance of bedroom rappers and you’ll see what I mean.



Production Tips & Tricks

Now, I wouldn’t be doing my job if I didn’t bring with this article some great tips and tricks you can use in your productions to get the most out of pitch correction. As we’ve explored above, it is a versatile tool that allows use in lots of different scenarios, so let’s have a look at some of the coolest ways you can use it! 


As with all things, it’s often the case that someone will discover a new and creative application for a tool that the original designer didn’t consider. This is exactly what happened when the likes of Cher and T-Pain used Auto - Tune in their way; instead of using it as a tool to correct a dodgy vocal performance without the listener noticing, they turned the correction to full and emerged with the now super familiar vocoder-like sound.


So how can you do this?


What you’ll need to do is set the Pitch Correction speed to its fastest setting to give you this robotic effect. However, if you want to have more control over the intricacies of the sound, you’ll need to use a pitch correction plugin that allows the target pitch (ie the scale or note that the input will be corrected to) to be controlled via MIDI input. So instead of the correct adhering to a user-defined but still fixed scale, the correction takes its cues from incoming MIDI signals. This could either be from a keyboard or a pre-recorded MIDI loop. This ensures there are no wrong notes, as if your incoming audio signal is more than a semitone away from the target note, it may get corrected to the wrong pitch if you’re using a fixed scale, and having a “mistake” even when Auto-Tune is applied makes the whole thing sound cheap and out of place.


But the signature robotic sound is tried and tested now, and some may argue it’s even getting old. However there are always new and exciting things you can try. 


Here are a few examples:


  • Artificial Double Tracking

Whenever I used to record vocals I would always double up my recordings. A doubled vocal line just adds more interest, and it helps add depth to your vocal track due to the two takes being different. You can also get a better use of the stereo field by panning your separate vocal tracks in different directions. 


So, by applying Auto-Tune to one of the tracks, you’re creating even more variation. Adding Auto-Tune will naturally adjust the way pitches and slurs between notes sound, even if you don’t have it set to the most drastic correction speeds. Where this comes in handy though is if you have one track of Auto-Tuned vocals against another track of unprocessed. The blending of the two signals sounds like a cross between double tracking and a sort of chorus or flange effect. 


For an even better result, add a few milliseconds(ms) of delay to the processed track, and it sounds even closer to double tracking. It’s worth bearing in mind that this could sound potentially too artificial on an isolated lead vocal, so perhaps consider it as a one off effect on a lead, or a good effect to use on backing vocals.


  • Creating Lush Harmonies

If you’re working with large vocal ensembles, or just lots of different tracks of harmonies (think of something like Fleet Foxes) then a great way to use Auto-Tune is to add it to a selection of your harmony tracks. The combination of some of the harmonies being natural and unprocessed, while others are Auto-Tuned gives more variation and bulk to your sound. You can adjust to what extent the various processed and unprocessed tracks are mixed, so you have complete control over the sound.


  • Taking it to the Extreme

Who says you have to only use ONE instance of Auto-Tune on a track? Have you ever tried adding more than one? Adding several with the correction speed at full can create even more extreme and drastic effects. You can try adding these in series and see how robotic a sound you can make.


I did this on one track where I pitched a wordless vocal line (ie I was just singing notes) up an Octave with loads of Auto-Tune, and it created an almost synth like sound.



  • Non-Vocal Applications

Pitch Correction and Auto-Tune are not reserved for vocals alone. A really cool effect you can use is to send a signal that varies in pitch to an Auto-Tune plug in which is set to single note correction with the speed set to full. The resulting sound will have lots of artefacts and glitchy sounds; the varying pitches of the source audio will mean there are lots of jumps in octaves and there will be interesting changes in timbre and tonality due to the large amounts of pitch shift.


The more processing you apply, the more drastic sounding results you’ll get. This can be a great way to add weird and glitchy sounding audio into your projects; using rhythmic input audio can work really well with this technique. You can even bounce out the resulting sound and add even more processing to create all sorts of odd and glitchy sounding effects or toned percussive hits. Experimentation is the key! 

______________________________________

Hopefully this guide on Auto-Tune and pitch correction has given you a better insight into the effect’s origins and uses, and as always we’ve thrown in some practical applications of pitch correction for you to use in your own productions. Here at Top Music Arts we are all about bringing you the latest and best tips and tricks for making your music as professionally as possible, so make sure you regularly check in so you don’t miss our best tips and tricks! 





Share this post



← Older Post Newer Post →


Leave a comment