I just started playing this last night. And I need to discuss something with you dev!
The female voice actor that voices Kim is a good actress. HOWEVER, the actual recording of the voice is a bad recording. I can hear the room noise (floor) of the recording in the mix. Her voice is muted and muddied as a result, and after just 4 text boxes I turned voices off.
The problem is likely that the mic input gain is too high, or possibly whoever is recording is using too much compression, thereby crushing the audio and raising the floor. It could possibly something that you are doing in post processing with the EQs and stuff, but I would need more information to confirm that.
Anyway, I can already tell after just a few minute playing just how much you love this game. That audio track isn't up to the rest of the game's standards. If you want help, and it's mic gain, or compression issues, I could probably explain the fix to you in a few minutes. EQ and post processing issues would be more complicated, but not insurmountable.
Or, you can just look up those issues on the net. (Mic gain is just rebalancing a knob, and compression is just rebalancing several knobs)