Place it right after a failed call setup, with the Discord Call sound first to set up the attempt, then follow it with the Classic Error sound to underline that the connection went nowhere.
關於此聲音
This clip plays the flat, repeating tone of a phone line that is already busy, running for about seven seconds after a call fails to connect. It feels abrupt and slightly awkward, like being cut off mid-conversation with nowhere to go. The steady beeping makes the rejection clear at once, turning a small everyday frustration into a short, recognisable sound.