What Is APT (Audio Performance Transfer) and Why Is It Useful?
By guest contributor Ronan Macdonald | Freelance writer, editor and musician
The world’s leading audio alignment plugin, VocALign is the ideal solution for getting multitrack vocals of all kinds perfectly in time. When more flexibility and control are called for, though, VocALign’s big brother, Revoice Pro 4, is the software to turn to.
Taking the concept behind VocALign to a whole ‘nother level, Revoice Pro 4’s quasi-magical APT (Audio Performance Transfer) algorithm enables not only the timing but also the pitch, volume level and vibrato of one audio track to be automatically applied to another (or as many others as you like!), instantly tightening up double tracked and ensemble vocals with incredible cohesion and transparency. It’s an innovative, powerful and creatively liberating system, and entirely unique to Revoice Pro 4.
Applying APT couldn’t be more straightforward. First, load your vocal tracks into the Revoice Pro 4 application, or use the Revoice Pro Link VST/AU plugin to sync Revoice Pro 4 to your DAW’s clock and stream audio between the two. (There’s also an ARA2 plugin for DAWs that support it, as well as the Revoice Pro APT plugin for Pro Tools, which we’ll come back to.) Then, set one track as the ‘Guide’ – your lead vocal, say, if you’re looking to match harmonies or a double track to it – and the track you want to conform to it as the ‘Dub’, and hit the Process button to create a new, Guide-matched version of the latter.
Much of the time, that’s all that’s required to get your double tracks or backing vocals tidily lined up in both the time and pitch domains, but if you do need to make any tweaks – perhaps loosening the timing or tuning a touch – the Process page gives you access to various APT parameters, including the analysis frequency ranges of the Guide and Dub tracks, timing, pitch and level matching tolerances, formant shift, and transient protection.
Larger-than-life vocals are a key component of contemporary pop and dance music, and thanks to APT, Revoice Pro 4 provides a comprehensive toolbox with which to turn even the most wayward multitrack performances into huge, super-tight stacks. And more subtle treatments are possible, too, such as modulating the pitch of a lead vocal using the melodic profile of another instrument in the mix, for example; or imposing vibrato lifted from a secondary source on an overly flat delivery.
Vocal stacking and processing are by no means the full extent of APT’s creative and engineering remit, however. For starters, Revoice Pro 4 is just as adept at transferring the timing, tuning and levels of monophonic melodic instruments – guitar, bass, brass, etc – as it is the human voice, making it supremely easy to lock a vocal to its supporting instrumentation or vice versa, or collectively straighten out related elements within a band. Here, it’s being used to apply the timing of a saxophone to the rest of the six-piece brass section:
APT also shines in the post production arena, where the ability to map the temporal and dynamic nuances of one audio track onto another makes it indispensable for carrying out otherwise time-consuming dialogue replacement tasks. Whether you need to overdub a noisy or badly captured location recording with a clean studio take, or replace one voice with an entirely different one, Revoice Pro 4 lets you transfer the precise timing, energy and even pitch intonation of the sketchy original material over to the dub without compromising sonic integrity or vocal character. It’s nothing short of miraculous, as ably demonstrated in this video:
With APT’s effortless dialogue syncing sorcery yielding significant savings on ADR studio time and session costs, Revoice Pro 4 has quickly established itself as a fixture on the Pro Tools-based workstations of movie and TV post production houses the world over. And the ADR workflow in Pro Tools is greatly accelerated by the use of the Revoice Pro APT AAX/AudioSuite plugin, which facilitates seamless movement of clips to and from Revoice Pro 4 right from within the DAW.
It’s no exaggeration to say that nothing else on the pro audio market can do what APT does – an empowering combination of time, pitch and volume alignment that puts Revoice Pro 4 in a functional and technological category of its own. As a listener, without realising it, you will have already heard APT in action on countless hits and soundtracks. And as a producer, quite apart from the flawless quality of the results it delivers, once you’ve experienced its intuitive, speedy workflow, you’ll never want to go back to the tedious manual editing of multitrack vocals or ADR recordings again.
If you want to try out APT, just download our free 14-day trial version of Revoice Pro 4.