SYNCHRO ARTS REVOICE PRO 4

Vocal manipulation is as much about pragmatism as it is performance. Revoice Pro 4 delivers some tools to keep our vocals moving together in harmony, not just in hard tune.
Review: Andrew Bencina
When I received my review copy of the fourth edition of Synchro Arts Revoice Pro I must confess I thought I’d be testing a straightforward vocal tuning application. Instead what I found was a hub of time and pitch manipulation for both spoken and sung vocal recordings… along with any other monophonic instrumental sources you choose to throw at it. 
In the broadest terms, Revoice Pro is an editing and processing multi-track program in which mono and stereo audio tracks are either processed (Dub and Warp tracks), act as analytical sources for control parameters (Guides), or are output as the product of one of these processes. Many tracks will end up being used for dual functions, with some producing new tracks that then act as guides or dubs for another generation of outputs. Alternate audio segments can even be archived in playlists of up to four layers to allow further experimentation. Things can get pretty complicated, if you let them.
STANDING ALONE
PreSonus Studio One, Logic Pro X 10.4 and now Cubase 10 users presently have the joy of using the integrated ARA 2 (Audio Random Access) plug-in version of Revoice Pro. The rest will simply experience it as a standalone application. On occasion you may run Revoice on its own during an editing session, but in musical applications it’s more common to run it synchronised alongside your preferred DAW. 
In standalone mode, Add audio file and Export modes perform as you would expect, along with the ability to save Revoice sessions with associated files. This is particularly convenient for later tweaks. In my case, I used the Revoice Pro Link and Pro Monitor plug-ins to transfer audio from my DAW into the multi-track layout of Revoice, then back again. While not quite automatic, configuring this connection was straightforward and worked as expected. 
Once a link is enabled, Revoice slaves its playback to the transport of the linked DAW, with a mix of all active tracks fed back to an auxiliary return channel in your main project. Despite the smooth setup I must confess to finding it tedious constantly switching between application windows. Of particular frustration was my instinctive use of the spacebar to stop the track while the Revoice window was in focus. On these frequent occasions the Revoice transport stopped while the rest of the project continued. A dual monitor setup may have helped but a mapped MIDI transport would have been ideal. 
If you’re prone to combining dense vocal arrangements with a desire for constant edit-ability, it’s worth noting that you’ll soon find yourself with two parallel mixes, running in synced applications. For those of us who fall short of the Chess grandmaster mind state, I’d recommend muting processed channels in Revoice, for necessary revisits, while dragging/exporting files back into your DAW track playlists. You’ll, of course, need to name your Revoice tracks accordingly to keep everything in order. 
A SHIFT IN FOCUS
If your idea of musical nirvana is a bluegrass quartet huddled around a single microphone then I may have lost you at ‘Hello’, but I think Revoice Pro 4 offers some musical options that should appeal to even the most traditional of recordists. Its function revolves around three primary ‘Processes’, launched for configuration by a quick press of B on your keyboard. As an aside here, fluent use of Revoice demands an engagement with its keyboard shortcuts; you simply won’t develop a smooth workflow without them. Once you’ve added/transported audio into your tracks you begin by selecting either the Audio Performance Transfer (APT), Double or Warp process and configuring the desired source and output tracks. What follows is a further settings dialogue for that specific processing instance. These settings configure either the algorithms used to analyse the pitch and timing of audio, in the case of Warp, or define the processing settings for APT and Double. All can be opened and tweaked at any time. Preset settings can be saved for different applications and shared with other users. While the factory settings were a good starting point, I preferred to refine and store my own settings. 
In the case of Warp particularly, much of the manual editing workload is defined by how well the algorithm analyses your audio, so it’s worth understanding how these settings are applied. Many of these adjustments result in immediate process updates and in a few cases a resultant lag in fader response was produced on all test systems. While this was described by the incredibly attentive support staff as a known trade off rather than a bug, I think it warrants further attention.
The Warp process is where all of your manually applied vocal tuning will be managed. It allows for shifts in both pitch and timing, time stretching and compression, the exclusion of silence, spill and sibilant moments from processing — elements that often produce artefacts in automated processes — and more nuanced adjustment of pitch expression through note transitions, note range and tilt, and the management of vibrato regions; maintaining a singer’s natural pitch modulation in stretched audio. 
As a long term user of the more basic Melodyne packages I thought Warp sounded great. I did experience a significant learning curve though, and the necessity of shortcuts and key modifiers didn’t ease this transition. There’s no question that it’s these pitch and time correction processes that will most benefit from ARA 2 plug-in implementation within a wider selection of DAWs. Notwithstanding, for those who’ve only used blunt force automatic vocal tuning options I sincerely endorse the more refined control afforded by Revoice Pro. The ability to manipulate and even redraw the curves of note transitions is at times a revelation and reminds you that often what we value is not necessarily perfect pitch, but rather increased control.
DOUBLE TAKE
If you invest a lot of time in vocal comping, or work with performers with limited budgets — or attention spans — it’s not uncommon to find yourself short of a suitable double track when you’re up to your neck in a mix. Not surprisingly, the Double process addresses this allowing you to create automatic double tracks by modulating the pitch and timing of the duplicate. A randomness control adds to the natural variation while a formant shift produces further tonal variation. Extreme settings can be used to achieve a range of very effective chorus effects. Create an extra double with heavier modulation settings and then ride its level in the mix as an accent or to just keep things moving. I found the processing to be equally effective with spoken and sung vocals, and monophonic instrumental parts, and comparisons with recorded doubles were favourable, if different.
I could write another entire piece on APT, alone. For me, this is the process that takes Revoice Pro to another level and perhaps more importantly makes it a useful tool for anyone working with music or dialogue. APT analyses the timing, pitch and volume energy of a Guide track and allows you to apply those control sources to a Dub. Each of the three has its own configuration settings and can be enabled or disabled. Protected areas can also be defined within a dub to prevent certain phrases from being warped, and the degree of pitch and timing control can also be automated. 
Sadly, the volume controls are less switchable and so if your dub has its own solo moments you’ll need to ensure both these and the corresponding guide phrases are edited into unique unprocessed regions. APT clearly owes a great deal to Synchro Arts ADR application VocALign Pro and is incredibly effective at matching spoken passages. 
I found a use for the Dialog mode on some double tracked rapped vocals and the result was impressive, even when the dub was soloed. While dialogue replacement is an obvious application, I can see many YouTube performers ‘dubbing’ the timing of their preferred audio performances to the guide vocals from the best visuals in order to achieve the best of both worlds.
STAYING IN BLEND
When used for musical recordings APT allows you to enhance the holy grail of ensemble performance; blend. I found myself disabling the pitch processing and tightening up both the timing and volume emphasis of harmonies and doubles. Just like my experiences with the manipulation of pitch transitions, the matching of phrasing and level reveals just how important these other elements are. Time can be saved using one tuneful vocal to pitch others and it’s interesting how many interesting moments can be revealed within lesser takes when this process is applied. I also tried a number of experiments, using: poorly recorded but strangely affecting demo vocals as guides to warp later studio recordings; demo harmonies and doubles from producers as guides for a different type of lead singer dub layer; and percussive synth tracks as guides for similarly phrased vocals. I’m sure I’ve just scratched the surface here.
A thorough downloadable PDF manual is available but the online help document is easier to navigate and compulsory reading if you hope to get everything out of Revoice Pro 4. I’d definitely prefer to use its tuning functions as an ARA 2 embedded plug-in but hopefully this won’t be too far away for most users. While priced at a professional level, audio demos and a free trial download have been made available to help you make up your mind.