Canon EOS-1D X Mark III Advanced User's Manual page 434

4.
Play back the voice memo.
(1) Speaker
Press the <
You can adjust the sound volume by turning the <
Press the <
Note
Multiple voice memos added to an image are played back consecutively.
Added voice memos cannot be erased by themselves using the camera.
Erasing images (
/ > button to play back the voice memo.
/ > button to stop playback.
) also erases any voice memos added to the images.
434
> dial.