Here is a fix I got from ppcgeeks. You need to call sprint and speak with tier 2 tech support and have them enable EVRC-B and set Home Orig to EVRC-B. This improved voice clarity, and speaker phone quality as well. Volume also seemed to improve. I have not experienced any negative affects due to this change or any additional drain on battery life. To view: 1) Open the phone dialer 2) Type ##DATA# or (##3282#) (do not need to press anything else) 3) When the screen pops up select view 4) Then select advance 5) Scroll down to you see EVRC-B and Home Orig (this is what need to be changed to improve voice quality). To enable EVRC-B: 1) Open the phone dialer 2) Type ##DATA# or (##3282#) (do not need to press anything else) 3) When the screen pops up select edit 4) You will be prompted for a password. 5) Sprint will need to give you the password, the password is also your MSL# 6) enter # given and save for later (maybe usefull if you root) 7) Then select advance 8) Tap to enable EVRC-B and then tap Home Orig to set EVRC-B there as well. 9) Press menu and select "Commit Modifications" so that the changes take affect. 10) You can now exit by press back. Hope this works for you. BTW I was not having issues before, but I did notice this setting worked better for me. This is the most current speech codec used by CDMA networks.