Put it at the very start of a travel segment, just before the title card or first spoken update, so it frames everything that follows. For a tense reveal, follow it with the Dramatic Dun Dun Dun, and for a lighter second cue, add a Bell Ding after the announcement lands.
關於此聲音
This three-second clip is the two-note chime from an aeroplane cabin, first a bright high note and then a deeper second note. It gives listeners a sense of attention and anticipation, as though an important announcement is about to follow. The chime has been used on aircraft speakers for decades to alert passengers before crew messages and safety instructions.