VariAudio 3's Smart Controls make possible much more than just pitch correction.
In my SOS May 2019 column, I considered how the overhaul of VariAudio in Cubase Pro 10 made routine pitch correction more efficient. But VariAudio offers more than pitch correction alone, so in this follow-up article I'll consider some of the corrective and creative options.
If you enable Show All Smart Controls in the Inspector's VariAudio tab (discussed last month), when you hover over a pitch segment in the Sample Editor you'll see Warp Start and Warp End Smart Controls, located centre-left and centre-right respectively. These don't change the pitch, but when grabbed and dragged left/right, Cubase will apply its audio-warping algorithms to time-stretch or time-compress the portion of the waveform bounded by the selected segment. (As you move the Warp Smart Controls for one segment, any segment adjoining the edge being moved is also stretched/compressed to compensate.) In a corrective context, this makes it very easy to make small timing adjustments to a performance. You can, for example, adjust the phrasing of syllables to hit an underlying beat/groove. As with quantising, a little can go a long way here, but if you're after that super-slick, polished vocal style, this can help you achieve it — and when you make these kinds of small timing adjustments, the results can be incredibly transparent.
More extreme timing changes can be used for creative 'rephrasing' of your vocal. You'll eventually come up against unmanageable audio artifacts, but it's remarkable just how malleable VariAudio can make a vocal — particularly with syllables that already include some element of sustain, since these can often take more extreme changes before the audio rot sets in. Audio artifacts are generally less of an issue when shrinking than stretching, but care is still needed if you wish to avoid the phrasing sounding unnatural.
Two options are worth exploring if your 'phrase changing' requires more precise control. First, as discussed last month, you can hover over the horizontal line Smart Control towards the base of the selected segment and split the segment with the scissors tool. Second, if you hold Alt/Option while hovering over the Warp Smart Controls and then drag left/right, the audio is not time‑stretched/compressed; instead, the positions of the segment boundaries are moved. Both options mean you can adjust the default pitch segmentation, and any subsequent warping can be applied to the waveform sections you've defined.
When composing, many people (myself included) add a piano melody as a guide for a future vocal. But VariAudio makes it easy for you to cross-check the pitch and timing of a recorded vocal to this MIDI-based guide, and you can even use it as a template for your pitch correction (see last month's column) and timing edits (described above) — though be aware that a vocalist might well improvise a little, so a good dollop of common sense is still required!
To display this MIDI reference in the Sample Editor, visit the Inspector's VariAudio tab and select the desired MIDI track from the Reference Track drop-down. The MIDI notes are superimposed on your vocal waveform and the VariAudio segments. In the screenshot, the MIDI track is labelled 'Piano melody', and although the vocalist stuck pretty closely to the pitch and timing of the guide, you should be able to see how you could use this to guide any further pitch and timing adjustments you wished to make.
Before we move on, note that the VariAudio tab's Functions drop-down also offers the option to 'extract' MIDI data — in other words, to generate MIDI pitch information from the VariAudio pitch segments and pitch curve. You might use this to create a MIDI-based line to double a vocal part, for example, or, via transposing and editing the MIDI, to harmonise with it. The extraction process is simple, but you might need to experiment with the pitch-bend data options to find the best match for the pitch-bend resolution of your target VST instrument.
For lead vocals in most modern genres, keeping every syllable audible is a must. In SOS July 2018 (https://sosm.ag/cubase-0718), I looked at using stacked compression to ease at least some of the pain of syllable-level volume automation, but pitch correction will usually be done before you get to that stage — and as you're already paying minute attention to the vocal you'll tend to spot words or syllables that need volume adjustment while you're in VariAudio.
You can now grab the Volume Smart Control, bottom-right of each pitch segment, and drag up/down to change the segment's level. As you drag, you get visual feedback showing the amount of gain adjustment you've applied. It's rather like clip gain in the Project page, but you can save time by doing multiple jobs (pitch, timing and level correction) in a single pass.
If you like pop vocals laden with ear-candy, check out the Shift Formant Smart Control, bottom-left of the selected pitch segment. Again, you can drag up/down, but this time you adjust the formant rather than the pitch.
In sung vocals, formants are essentially harmonic elements created by the size/shape of the singer's vocal tract, so adjusting this is a little like shrinking/growing that vocal tract. Larger vocal tracts tend to sound a little more 'male' and smaller ones either more 'female' or 'younger', so you can tweak this setting to change the character of the voice subtly or considerably.
This is useful if you want to give backing vocals sung by the same singer a slightly different sound, but perhaps the most fun is to be had by using formant shifts as a deliberate ear-candy effect. For example, if you have a phrase with multiple short syllables, an interesting spot effect is achieved by applying formant shifting to alternative syllables (pitch segments). Crank the Shift Formant Smart Control well above 50 percent and you get an obviously artificial — but not unappealing — result.
You can combine various Smart Tools to enhance this too. For example, you could use the Scissors tool to split a sustained note into a number of shorter segments that fall exactly on the musical grid, then apply extreme pitch quantising and perhaps pitch shifts to make it more synth-like, before finally using the Shift Formant control to add a further twist.
This sort of extreme vocal processing is very much a matter of taste, so I'll leave you to decide where the boundaries of aesthetic decency lie on that front! But don't be scared to experiment — the VariAudio tab's Functions drop-down menu includes several options for resetting your edits, both for the whole audio event and just the selected segments, so if you need to scrap things and start again, it's easy to do so.
VariAudio 3 is undoubtedly a highlight of Cubase Pro 10. It's a powerful, flexible and, with the new suite of Smart Controls, super-efficient tool for all sorts of corrective and creative vocal editing. Indeed, taken as a complete vocal editing suite, I think Steinberg have set a pretty high bar for others to aim at. Oh, and it doesn't have to be just for vocals; other mono (not stereo) and monophonic (single‑note lines, not chords) audio recordings can also be subjected to some of this VariAudio magic.