I also have A similar problem. I can hear the audio in conversations, but it is extremely quiet and very muffled, as if it was being hear through a wall. If I pan the camera around to get the camera closer to A character I can sort of hear them better, but still very poorly.
This happens at all locations I have visited and in all my save files. I even tried making A new character to see if my initial character's files were bugged but it seems to be universal.
I tried messing with the audio setting but to no avail. I'm going to try A reinstall next.
Here are my PC specifications:
Operating System
Windows 8.1 Pro 64-bit
CPU
Intel Core i5 4570 @ 3.20GHz 26 °C
Haswell 22nm Technology
RAM
8.00GB Dual-Channel DDR3 @ 533MHz (7-7-7-20)
Motherboard
ASUSTeK COMPUTER INC. Z97M-PLUS (SOCKET 1150) 28 °C
Graphics
DELL ST2420L (1920x1080@59Hz)
3072MB ATI AMD Radeon HD 7900 Series (Gigabyte) 26 °C
Storage
119GB LITEONIT LCM-128M3S 2.5" 7mm 128GB (SSD)
119GB SAMSUNG MZ7PD128HCFV-000H1 (SSD) 23 °C
149GB Western Digital WDC WD1600JS-00NCB1 (SATA) 35 °C
Optical Drives
No optical disk drives detected
Audio
Realtek High Definition Audio