Speaker Test
This speaker test page plays simple browser tones so you can check whether audio comes from the expected side, whether output is distorted and whether the current device route is correct.
What the speaker test can confirm
A left-right-center playback routine is useful for verifying built-in speakers, headphones and Bluetooth routing without installing any extra apps.
It is especially helpful during second-hand checks, repair pickup, meeting setup and any fast handoff where you need to know whether audio output basically works.