Breakthrough! Or a breakthrough of sorts, at least...
First, I found that I had this problem not only in Baldur's Gate and Dragonshard, but a similar one in Fallout 3 (I couldn't hear character voices in dialogue).
I thought, okay, let's see where exactly this goes wrong, so I uninstalled the entire installation, determined to walk through the installation bit by bit, to see when the sound would go faulty. With vanilla
BG, no
TotSC, there was no sound. I pressed "done" anyway, when I had built my trial and error character. On the prologue-screen, I thought I heard something.
Right I was. The voice-volume wasn't gone, it was just turned down very low. Now's the tricky part: Where? The voice-settings are fine in the config, in the game menu, and in Vistas Volume Settings. I'm using a 5.1 system, so I thought: "maybe voices only come from the central speaker, and that's turned down?" It was turned half-way down, but turning it up full didn't help very much.
What the #"&%"&% is the problem? Which system controls can turn down the voice-volume or properties hereof in only some games? Is it my soundcard? Or what? This is driving me crazy, as I now realize it doesn't only affect old games, but also new games like Fallout 3
"I've heard people complain that the game [the new Prince of Persia] is too easy, which seems odd to me, since I died more times than The Nameless One in a smoothie-maker."
- Yahtzee