audio impedence detector (smart cell-phone ring)

Many cell phones have ringers which sound quite loud in open air and yet can be nearly inaudible when placed in a pocket. This is a consequence of poor impedence matching between the phone's ringer and the material in the pocket. While there would be obvious limits to the phone's ability to detect such a condition, it should be possible for the phone to analyze the audio return on the ringer, speaker, and microphone and use that to set the ringer volume appropriately.

I know that phones already have options to have the ringer escalate in volume, but if the phone doesn't get audibly loud until the third ring there may not be time to answer it.