My notebook uses Realtek's ALC883 HD Audio (currently using the latest official driver 5.10.0.6526), which has support for EAX 1 and 2, so I usually leave environmental effects enabled in games like this. In Planescape though, this leads to some very heavy echo during most dialogue scenes, at least in the beginning of the game where I am now. So, two questions:

If I disable environmental audio (which fixes the echo for me), does that have a significant impact in how nice the game sounds?

And a related question, considering how widespread Realtek sound chips are (seemingly every notebook and desktop motherboard uses them from what I can tell), are there no custom drivers anywhere that offer better game support than the official drivers do? I ask because there are a lot of other games, like Fallout NV, that also have annoying sound problems.

I'm running WinXP Pro 32-bit