Say where you were, what you heard, and what else was happening. A short sound clip helps. So does admitting that the microphone was in your pocket. The archive is editorial fiction; draft contributions remain in your browser rather than going to a moderator.
What belongs in a field note
Keep the place, sequence, and your interpretation separate. Write down what happened before the sound, what you heard, and what the room did afterwards. A useful description leaves room for another reader to reach a different conclusion.
Start with a recording
This is a fictional discussion archive for people with a noise to identify and a theory to share. Read the recorded threads, try a sound sample, or compose a local draft. Nobody here expects your first explanation to survive the replies.
Listen to the sample collection and compare the notes. The labels concern the sounds; the stories concern the people who heard them.