Some days ago we had a discussion on how to avoid to hear remaining plugin audio (“audio tails”) when switching to/from a rackspace, which is caused by the saved/frozen state.
I had a similar challenge yesterday evening, when preparing a rackspace, which saves the plugin state with remaining audio and continues to play this when reentering the rackspace.
I figured out, that some of the Arturia plugins have a Host Automation parameter “VST3_CtrlAllSoundsOff” which helps in this situation 
Attached you’ll find a demo rackspace which contains a button widget which is mapped to VST3_CtrlAllSoundsOff an does the trick by defining the initial state to “this Value” = 0.0
Every time you enter the rackspace, the button is triggered and therefore suppresses any remaining audio tail in the plugin state
You can also push the button manually…
You can check out with the attached gig file.
SoundOff.gig (101.2 KB)
Have fun!
BBB