Tempo Changes

I’m using Studio One and importing a MIDI file. After I import the MIDI file into the Synth V vst plugin, I then “synchronize tempo with host”, however Synth V seems to ignore any ritardandos or accelerandos I have in the score. I just paid nearly $500 for this software and 4 voices (so I could get SATB sounds).

Am I missing something in the setup?

If you use the current beta release you can leverage the ARA bridge, which will automatically synchronize tempo and playback.

Otherwise, the best thing to do is add tempo markers manually which match your DAW project by double-clicking on the time axis (more info: Setting Up the Score - Synthesizer V Studio Unofficial User Manual (synthv.info)). Please note that without the ARA bridge, a gradual tempo change is not supported and must be done in a stepwise manner.

Forum thread about the upcoming feature and ongoing beta:

News article for the beta and download links to beta installers:

Setup and usage instructions:

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Thank you, Claire. I am having difficulties getting the plugin to load. I’m getting an error reading: “Failed to start the plugin in ARA mode.”

I also saw this once (though I’m only using the trial of Studio One for now), but it went away after restarting the DAW. I didn’t see the same error again after that.

You can also try running Studio One as administrator if you are using Windows.

If you want the Synthesizer V VST plugin to follow your tempo changes in Studio One there are two ways to do this:


  1. Make ALL your tempo changes first inside Studio One.
  2. Make sure there is at least one midi track in Studio One, or just make a dummy one if not.
  3. In Studio One hit file>convert to>midi file and save it as a MIDI file.
  4. In the Synthesizer V standalone (not the plugin) hit file>import and open the MIDI file and save that as an SVP. (You can check first to see if the file has the tempo changes, which it should.)
  5. In Studio One load a blank instance of the Synth V plugin, and then inside the plugin hit file>open and load the same MIDI file, and you will see it has the tempo changes. You can then program your voice material in the plugin and it will follow your DAW, but it won’t follow any new tempo changes you make, so you have to get all the tempo changes first for this method.


  1. Make all your tempo changes first inside Studio One
  2. Make sure there is at least one audio track in Studio One, or import or make a dummy one.
  3. In Studio One, go to effects (not instruments) and drag the Synthesizer V ARA effect onto the audio track. You don’t have to convert the audio to a voice if you don’t need it.
  4. Now you will also have the tempo changes in Synth V inside of Studio One. But you still cannot make further tempo changes in Studio One and reflect that automatically in the ARA plugin. However, if you keep the audio track available, every time you make a tempo change in Studio One, drag again from the ARA effect to the audio track, and it will update the plugin’s tempo map.

Obviously the second method is better, because you can update the tempo, and also has better following of playback sync with other material in Studio One. But it is still not as perfect as just always following your tempo automatically. The old method is still useful if you want to work in the Standalone program and later open it in Studio One, or render the audio to import into Studio One, and be in sync.

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