Siri Confirmation Tone
Sometime in the last few months I noticed our HomePods would respond to some requests with a new “ding” tone. I couldn’t make sense of the logic for when the ding would play versus when Siri would respond with the traditional, spoken “Okay” message, but it turns out the answer is right in the HomePod 16.3 Release Notes:
Siri confirmation tone will now play to indicate when smart home requests are completed for accessories that may not visibly show a change or are located in a different room.
16.3 shipped towards the end of January 2023 and I notice this most often with our Goodnight scene that turns off a number of lights in other rooms.