I have the same issue (I think)
My ear piece volume is very loud and the sound is great but when it comes to exterior sounds the Inspire makes, it is really horrible!
My ringtone, email and text sound notifications are so low in volume (With the volume set at the highest level for all) that I don't even notice it has gone off.
I just bought it 3 days ago and coming from the HTC HD2 I am really disappointed. I missed 6 calls and dozens of texts and emails just today because I can't hear it when it's in my leather holster, same holster I used with the HD2.
I'm not sure what to do to fix it and I would really appreciate any suggestions to improve the sound levels. Otherwise I'm gonna return it before my 30 day trial period expires. A phones is useless if you can't hear it.
HTC One X on AT&T 2.20, Bootloader unlocked, Rooted, TWRP & SU (so far)
HTC One X on AT&T, 1.85, rooted and Bootloader unlocked.. BRICKED 1-17-13
Samsung G/T P3113, Rooted and Jelly Bean
RETIRED-HTC Inspire 4G on AT&T- Dropped and shattered screen
Running Cyanogenmod 7 on 2.3.7
RETIRED, HTC HD2 T-Mobile USA
Constantly changing roms....
RETIRED! AT&T Tilt
KAISER WM 6.5 OS 5.2.21500 by Medkid V1.6.2F