An iPhone of the future could change its volume all on its own by detecting how near or far you are to it.
"Adjustment of acoustic properties based on proximity detection," a patent application published Tuesday by the U.S. Patent and Trademark Office, describes how the iPhone's promixity sensor could be used to automatically change the volume or even switch between the receiver and the speaker.
Holding the iPhone to your ear would lower the volume through the receiver. Moving it slightly away from your ear would raise the volume. Putting the phone down and moving away would switch the audio output to the speaker. Moving further away would increase the volume of the sound piped through the speaker.
Transitioning from the receiver to the speaker or vice versa would fade out one while fading in the other, ensuring that the switch is smooth and seamless. The phone's sensor could also adjust the frequency of the sound depending on your distance from the device. For example, the lower frequencies would be boosted as you move further away from the phone so that the quality of the audio is maintained.
The phone might detect your proximity by measuring infrared light or low-intensity sound waves or by calculating how much light bounces off from you and hits the sensors. The iPhone and other touch-sensitive devices could also tell when your face or ear is up against the screen as another way to determine your proximity and thereby adjust the volume.