That makes sense. I was also wondering about it perhaps using something legacy with it being an older mod. I did find a few others in addition to confirming what ltntai mentioned with the train horns. Cessplane, Farming Pack, MAN truck go (at least partially) silent when the Effects/UI slider is brought to 0. Anyways, I guess the point I'm trying to make is if that slider is labelled "UI vol" it may not actually be limited to just the UI sounds and could cause some confusion. I'm not the expert but I wonder if there's a way to truly separate out the "UI vol" and "Effects Vol" into two different sliders? Or perhaps maybe a checkbox that enables/disables the UI sounds? Just some thoughts. Thanks for all that you do!