Ambient adjusted volume control for in-vehicles messages

摘要

The reproduction sound level of high priority messages such as navigation instructions, parking aid signals, and back-up warning signals is controlled based on the average ambient sound level in a vehicle. A sound level calibration table provides priority gain values for setting the programmable gain of a gain controller to ensure that messages are reproduced at a sound level which is relatively greater than ambient noise level by a predetermined target difference which is consistent for all levels of ambient noise. The target difference may be modified according to user preferences.