I’m starting from a track that’s already in Logic, not SV. The tempo changes a lot, and because SV’s tempo control is so simplistic, it can’t stay in sync. Even if I produced a static wav from logic and pulled it into SV, I don’t see a way to make a tempo map inside SV that’s going to work. I guess it might be possible if I could turn off all concept of tempo in SV and use absolute times, but that would be extremely unpleasant to work with, having to align every beat in milliseconds manually! I’m also quite likely to want to change the tempo, or reorder parts of the song, and not be nailed to sync with a fixed audio file. All this is standard production processes, it’s not like it’s anything new. I understand that some tempo things might be tricky (like Logic’s smart tempo, which I’m not using), and I would be quite happy with it working with some limitations, but at the moment I literally can’t even get a single note to play in time – starting from the same initial tempo, by the time the first sung note arrives, SV is already over a bar out of time.
That article is suggesting something very simple – if you have a fixed tempo for the entire duration of the song, it can stay roughly in sync, but this is more coincidence than any real sense of sync. I do have some tracks that are like that, but not the main one I hoped to use SV for, which contains a tempo map extracted from a live performance, and doesn’t maintain the same tempo for more than a couple of beats at a time.
So you want to write in the DAW in free time and somehow have SynthV know the whole tempo map in order to render the vocals which is not instantaneous? I agree this would be super-cool.
I realise any synth or sample player will follow tempo, but they are fundamentally different insomuch as they are retriggered note-by-note. SynthV, by its very nature has to render the whole file in advance.
Most plugins are little more than signal processors (or generators). They accept either MIDI input or an input signal, and then create or modify the signal accordingly in real-time.
SynthV is not a real-time synth. It must render its output before playback starts, so of course if the tempo changes during playback it will no longer match.
The main limitation is the inability to change tempo gradually. If you change your gradual tempo changes to stepwise ones and enter the same tempo markers in SynthV Studio then the timings should line up without issue (barring any DAW compatibility problems, which can be easily worked around by rendering a wav file).
I wouldn’t expect this to change any time soon, SynthV’s main competitors don’t even have DAW integration, all use the same “render before playback” approach, and (as far as I can tell) all only support stepwise tempo changes.
(to be clear, I know Vocaloid5/6 has DAW integration, but as far as I’m aware most users who have Vocaloid4 still use the V4 editor which is standalone-only, so I’m considering V4 the more relevant competitor software from a user-experience and composition perspective)
I’m mainly thinking of Melodyne here, which (while it’s not a synth) has more or less the same approach (own timeline, pre-renders), but has no problems with sync. I would have zero objections to waiting for SV to render a “frozen” track before playback (while it may not be instant, SV is still quite fast, and most DAWs can do this for their own built-in tracks anyway), as that would be a massive improvement on what I can do at the moment, which is nothing at all. It could also possibly provide a low-quality mode with instant-ish playback that might make it much easier to work with, and then add a rendering step to produce a high-quality version.
As you say, I could try to make step tempo change markers, however, SV could improve this massively by importing a snapshot of the entire tempo map from the host, or perhaps via a MIDI file (though MIDI file imports don’t currently seem to retain tempo?); I really don’t fancy creating several hundred tempo markers manually, and be faced with the threat of accidentally knocking the whole thing out of sync if I so much as breathe on it… I don’t see that the synthesis method has any bearing at all on tempo management.