Synchronize tempo with host - tempo changes

Hi, I’m using Pro + Kevin to prototype some acapella learning tracks for a barbershop chorus. I’m creating the tracks from midi exported from Musescore, adding lyrics in Studio, then running through Reaper as a VST to generate tracks. It’s working and sounding really good for simple tracks

Some of the songs have a “free” feel to the tempo, and I’m tweaking this in Reaper, but using Sync to host is not bringing these in, just the initial tempo.

I’ve seen some workarounds using export and re-import, but this is a real waste of time. Is this the best I can do, or am I doing something wrong with the vst host? Or maybe I have to be more precise in my original midi creation and stick to my choices?

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Since Synth V has to render the vocals in advance, it can’t respond to tempo changes in real-time.

I think the best option you have is manually adding the tempo markers from REAPER into Synth V. You can add a tempo marker by double clicking on the timeline above the piano roll.

For more details see the unofficial manual: Setting Up the Score - Synthesizer V Studio Unofficial User Manual


Thanks, yes I wasn’t expecting it to change in real time (although that would be great), I was just hoping the sync button would bring in the full tempo map.

Manually adding the tempo markers is too much work as I have created a tempo “envelope” so it’s changing almost every beat. I’ve changed my workflow to create the midi files with tempo in Reaper first, before importing into Synth V. It’s fine as a workaround for now, and results are decent enough.


Creating the midi in REAPER with the correct tempo and importing it is a good idea.

It seems some plugins and DAWs integrate well like Studio One and Melodyne, so it’s definitely possible to import/export tempo maps.

I think for that to work, both host and plugin need to implement ARA correctly. That could be a feature request for Synth V.