Tire sfx event with a "terrain" parameter

[Alcibiade]

Indeed, that’s not the best method. Maybe one day my suggested feature will be implemented and it will be possible to do that directly. But in the meantime, in your case, I think I would go with a discrete (labelled) “terrain” parameter, instead of continuous, and set an attack and release (AHDSR) on each instrument. The transition would then have a fixed timing, which would probably even be better than your transitions driven by the parameter’s value: after all the car can’t be at the same time on asphalt and dirt… The only drawback is the first time the event will play: the attack would also apply. But this could be acceptable if this attack value is sufficiently low.