I have notice some people having issue with having no sound comming from the speaker. Two days ago this issue started happening to me as well. With mine the sound would all of a sudden start comming through the ear speaker instead of the loud speaker. Only solution i found at the time was to restart the phone or make a call and put it on speaker and hang up then sound would come back. All of a sudden it did it today. So i back tracked to see what might of caused the issue. I only did 2 things before i noticed that i had no sound comming from the loudspeaker. I used the play store and did a hangout using google plus messenger that came with the phone. I played with the play store a while and was not able to re create the problem. Then i played with the hangout using the messenger that is pre installed on the phone. Bingo. I was able to duplicate the problem 100 percent of the time. When i join or create a hangout and then leave that hangout i have no sound comming from my loud speaker.
So i know in my case the google plus messenger is causing my phone to lose sound when i use it. I even tried doing factory reset and not installing any other apps on phone and was still able to duplicate the problem when i used messenger in a hangout. I havent seen any other apps that is causing this issue but messenger. There could be others. If you are having this issue with your razr maybe what i have found on mine may help you with this issue.
I did try doing a search to see if anyone else has found this bug but didnt find any. So hopefully im not repeating what somebody else has already found.