Juli Clover, MacRumors:

In a support guide, Apple says that the AirPods Pro may play a sound every so often while in the case to ensure the microphones and speakers are working as intended. From Apple:

To help ensure that your AirPods microphones and speakers are operating at their best (for example, to help provide high-quality hearing test results), your AirPods may periodically play a quiet chime when they’re in their charging case.

Information on the mysterious chime was highlighted on Mastodon after Apple’s unclear AirPods sounds were discussed on today’s ATP podcast. As noted on the podcast, Apple does not have an established guide that provides insight into the different sounds that the AirPods make, so it can be confusing.

Years ago, Apple was a successful company and documented how their products work. These days, Apple is struggling financially, and alas can no longer afford to produce something even as simple as an interactive web page with examples of the sounds that AirPods make and explanations of what those sounds mean.