I almost threw this thing out the window about 2hrs ago because of sound issues. I have been back and forth for the last 2 days now with this phone whether or not i am going to keep it and make the jump from my 5s/iOS to WP8...I am liking a lot of the stuff about the phone but there some things that bug me a lot. So today was pretty much a great day with it, mainly sitting at home watching football so i played with it non stop for the last 8hrs or so(battery only dropped to 55% from 100!) Then i get a couple calls from the on call phone at work while i was taking a shower, no big deal, nothing to do with the phone at all, just me missing the call. Then i go to listen to the voice mail. I had to listen to that damn thing like 7 times before i finally heard the damn message. 3 times i kept turning the volume up and there is barely any difference, the last 3 times i was to the point of maxing the volume out while trying to get it on the right position on my ear to actually hear the dam thing.
Things that are extremely annoying about sound with the 1520...
-The volume scale goes fro 0-30 from off to loudest. Barely any increase is noticeable until you get up 20 on the scale. One the other hand, if your phone is sitting there with the volume at 10 and your phone is ringing it is loud. They need to completely seperate the ear piece volume and the ringtone volume. If they did that's great, but I don't see it anywhere.
-Overall sound loudness is weak, good enough though for me though. I rarely use the speaker phone on phones so no biggie there.