INFORMATION PROCESSING DEVICE, VEHICLE, AND INFORMATION PROCESSING METHOD

A vehicle includes a first speaker, a data communications device, and an information processing device. The information processing device executes the followings: receiving a user operation to make a volume change of audio output from a first speaker provided in a vehicle, the user operation being input into a volume adjustment portion; and while the data communications device outputs audio from a second speaker, notifying the data communications device of the volume change made by the user operation input into a volume adjustment portion.