updated 12:10 pm EST, Thu January 22, 2009
Apple Adaptive Mic Patent
The US Patent Office today published an Apple patent filing that reveals the company having developed a system to auto-tune sound volumes. Citing the problems with having to constantly adjust the volume of a cellphone's ringer or a notebook's speakers to adapt to noisier or quieter environments, Apple suggests that a sound sensor like a mic can be used to determine the ambient noise level on startup or over time and change the base volume to be audible based on nearby conditions.
The system wouldn't necessarily lock the volume to its own preferences and could account for the user's own choices for relative volume when setting the new sound level. It could also change settings when a user plugs in headphones or recommend a switch to this kind of listening when it detects an echo that might make listening difficult. It could alternately try to actively cancel the outside echo through changes to its own sound output.
Credited to Peter Mahowald, the patent application was first filed in July 2007, or shortly after the launch of the original iPhone. Apple hasn't used the technology so far and hasn't made indications of any plans to use it in the future; however, the company already uses ambient sensors to detect light for the displays on the iPhone, iPod touch and most Macs as well as to illuminate MacBook keyboards.