What is the sad violin sound called?
It is usually called the "world's smallest violin" — a short, deliberately over-sentimental solo violin phrase played to mock a minor complaint. The joke is the mismatch: orchestral tragedy scoring applied to something trivial. Most versions are a few seconds long and descend in a minor key.
Hear it
The gesture comes from a much older idiom — miming a tiny violin between finger and thumb to signal insincere sympathy — which existed long before it became an audio clip.
The most widely circulated recording is a commercial library cue, which is why videos using it are regularly claimed by automated copyright systems. Because the phrase is a musical gesture rather than a specific composition, a re-recording is straightforward and carries none of that exposure.
For editing: start it under the last two or three words of the complaint rather than after. Overlapping the dialogue is what makes it read as a comment on what was said rather than a scene change.
Commonly called
People search for this under a lot of different names — all of these find it here: