There could simply be something inside the speaker holes, for instance, I've dropped my phone in water while listening to music and the sound appears muffled. Or perhaps you've been to the beach or gotten some excess particle in there. My point being is, make sure that there isn't anything up inside the speaker holes or further back inside of it.
If there isn't anything there it could be that you have busted a speaker or there may be a software issue. Nonetheless, it wouldn't hurt to get it checked out by a professional.
Hope this helps! Have a great day!
crwdns2934105:0crwdne2934105:0
crwdns2934113:0crwdne2934113:0
crwdns2915270:0crwdne2915270:0
crwdns2889612:0crwdne2889612:0
1
crwdns2942205:01crwdne2942205:0
Is the volume on max on both the speaker and the phone? And what did you do a factory reset on? Also what speaker is it?
crwdns2934271:0crwdnd2934271:0 Cameron crwdne2934271:0