You can use the deletevehicle command on triggers as well (if it's a trigger sound)
So, if you want to permanently get rid of it, you can set up some other condition and use deletevehicle trigger1.
If you wanted to simulate it turning off and turning on again, use Armstrong's method. (ie have it play for a set length of time, move it. Trigger fires again--->move it back)
Actually I spoke hastily....this would work only if you had the trigger and the sound as seperate objects.