Apple is trying to make the vibrate alert on the iPhone silent. Currently the silent mode on an iPhone can be starling as the sound levels of the vibrator are so loud, particularly when placed on a table of similar.
The company has filed a new patent that covers an attempt to monitor sound levels generated by the vibrator and adjust the mechanism if it is too loud.
Apple's method would see the vibrations be monitored by a microphone or movement sensor. If the sensor deems that there is an unwanted disturbance it could turn down the vibrator inside the phone to reduce the reverberation.
"The sensors can determine If the vibration is causing the phone to move or generate a noise louder than ambient noises in the surrounding environment," explains Apple Insider.