No one can hear me when I have this case ...
921936
No one can hear me when I have this case on. I had to remove it from my phone, so I can't have a conversation
2903881
When I put my phone in the case no one could hear me and I was not able to hear anyone.  I think it is a design issue.  Customer Service was quick to offer me a replacement or refund my purchase.  I pulled the screens covering the sound ports and now the case is useable but is not so water proof anymore but still offers quite a bit of protection.
2121719
Everything sounds muffled, and no one can hear me when I talk. I hope the case is really as "lifeproof" because that is the only thing it will offer. Everything else is terrible.
4873377
The case is great but the bad part about it when you talk to someone you can't hear anything the other person is saying
1786203
I was really excited for this case and I'm sure it is capable of everything it claims. However once it's on your phone it is impossible to hear people clearly or for them to hear you. It sounds like the person on the other end has a bag of marbles in their mouth and I was told I sounded the same. If your Bluetooth is surgically implanted in your ear or if you don't plan on using your phone to talk than this is the case for you.
744536
Not sure why, as nothing appears to block the speakers, but for some reason, with this case, users on the other end can't hear you very well. They say it sounds "muffled" etc. For whatever reason, speakerphone works as well as talking through headphones.

Found another review elsewhere (after buying it) in which another person reported the same issue [...]
Tested it in and out of the case, restarting, looking up things online, etc. and the case definitely is the issue. Phone works fine out of the case. Maybe the wood and something to do with how that affects sound as wood isn't present in many other cases?
750357
This case is SO cute, but does not allow people to hear me when they call. It must cover the speaker too much. So disappointing.
484015
There is no cut out for the microphone. Everyone can hear me way better with the case off. Stay away from this one
1235273
It's been 5 months, now I have to buy a new one because no one can hear me with it on.
3777362
When this cover is on, I can't hear anything on the phone. I think this cover blocks the phone signal
2862828
This is one of my favorite case for my phone cause nobody can read my text or look at who's calling.
4659622
Callers couldn't hear me when I used the phone while it was in the case. The case didn't work for me.
435861
When in speaker mode, I must remove case for people to hear me on the other end of the line.  Bought the companion car mount which works well, but is useless if I have to remove the case.  This is an accident, literally, ready to happen.
3325987
The case is waterproof, that's not the issue. The issue is, you can't hear out of it! I have tried everything. I can't hear who I'm on the phone with, and they can't hear me.
959762
I like how the case looks but I can't talk on my phone with it on because I can't hear the person talking to me.  Sad to pay for something I can't really use.
2612146
Initially the case was fine and served it's purpose. However, 4 months after owning it people can't hear me when I talk. I would not purchase another one.
4916777
Due to the protection on the speakers the person on the other line could not hear me. The off/on button and volume buttons are hard to press on. The case is hard to remove.