iPhone 5, iOS 7: Alert/Ringtone volumes low...

I updated my black 32gb iPhone 5 to iOS 7 last week and one of the very things I noticed was how many missed calls/texts I had. I couldn't understand why until I went to change my tones to something more attention grabbing.... I noticed that the volume of the alerts and ringtones, including the classics, are too low to be useful. At first I thought it was my imagination until I went to work and my coworkers IDENTICAL phone started ringing, and boy did it sound great. Clear, crisp, loud. I compared her phone running iOS 7 to mine and there was a huge difference in the ringtones & alerts.

So, now that I know it's not just my imagination - I have spent all day looking for other people having this same issue. I have found a few, but nobody has a solution. This is occurring on not only the iPhone 5 but also the iPhone 4 & 4s - but not to everyone. That would lead me to believe that there may be a hardware issue with my phone but here's the rub: It sounded loud, crisp & clear when I was using iOS 6.1.4. So a software issue? If so why wouldn't it be affecting everyone and not just a few of us? This is beyond baffling and frustrating...

Before I take this phone to Apple (thank goodness it is under warranty) I was wondering if anyone here has experienced this issue and FIXED IT. What I've tried so far is turning the volume down and up, turning up all volumes not just the ringer and restoring the phone to factory settings through iTunes. None of it worked (thus this post), therefore as I said if anyone has a solution to this prior to me making the several hour journey to the Apple store I would love to know what it is. Thank you in advance.

Shawn G