I can't test this because I'm deaf, but I happened across this site...
To be specific:
The phone ringer volume was unusually quiet although music and videos sounded normal. There is a hidden feature that lets you raise the volume much more. You can select the “loud” setting on the ringer then go into “profiles” on the main menu, then click “pre-loaded” , find the ringer your using, click on the track ball, then use the side volume keys to raise it even further. It’s natural to think the “loud” setting is the highest it can go. Why did they make it so hard to raise its volume even higher?
Did this work for anyone?