Over the past few weeks, I have noticed that the call volume on my iP6 has seemed quieter and quieter at max volume.

I was at a trade show this week and had to make a call in a moment's gap in appointments, yet could hardly hear the person on the other end (on a landline) and found that again yesterday with another call.

Anyone else experienced that?

Volume is set at max and is fine on Speaker or when I use my Plantronics Bluetooth headset. It's just the 'normal' ear part that seems to be going quiet.