A vehicle system may be connected to a mobile device over a data connection and an audio connection, and configured to, responsive to a vehicle volume change, request over the data connection that the mobile device provide an audio indication at device volume over the audio connection, and reproduce the audio indication by the vehicle system, at vehicle volume, to indicate a loudness for audio played back from the mobile device. The mobile device may be connected to the vehicle system over the data connection and the audio connection, and configured to receive the request over the data connection that the mobile device provide the audio indication over the audio connection, and provide the audio indication at device volume to allow the vehicle system to reproduce the audio indication at the overall volume of sound played back from the mobile device through the vehicle system.