I posted this in a previous topic I started about this issue, but I figured I should post it here so that more people see it. My apologies if someone has already posted this, but I searched for a solution on these forums last night and I could not find one. This is for those that get no voice when Esbern speaks and he is bugged to high hell thus preventing you from moving forward in the quests.

I fixed this problem in my game (or so it seems, but Esbern finally has a voice and I reloaded back to the bugged first meeting with Esbern and it worked, he opened the door himself) you need Oblivion installed for it to work tho since OBMM won't install without Oblivion on your PC.

Install Oblivion Mod Manager
Open it and in utilities select BSA browser, go to your Skyrim folder and select "Skyrim - Voicesixtra" in the Data folder.
When OBMM loads it, select "Extract All" and extract it in your Skyrim Data folder.

Load up your game and see if it works when you talk to Esbern. It did for me and he got his voice back and seems to not be bugged.