Now, the GOG.com Duke Nukem 3D works fine, so this isn't a question about the fresh install.
Rather, it's the installation of the High Res Pack that is causing this problem.
The music is fine, but all the sound effects (inc. duke nukem's witty remarks) are very staticy, and even almost echo. I've played under eduke3d setup, changing the # of voices, bit rate, and sample freq, but nothing fixes the problem.
I'm running Vista. Any ideas?

I think the nicest part of the HRP isn't the high res, it's the controls.. going back to using arrow keys and no mouselook was too difficult for me.
I know there's a 'mouselook' feature in the original game, but its an attempt at best...

Heh, I play the original game using typical WASD setup. Works the same as the new one. Just make a few adjustments to the config file.

I think the problem has something to do with the way eduke32 (and jfduke too, I think) handle Directsound. They seem to support the Windows XP version of Directsound directly but not the Vista/Windows 7 version. The latter operating systems only support the XP version of Directsound through emulation (as I understand it), which works fine with most apps, but not eduke32 apparently. The solution is to install OpenAL, an open source API for audio (much like OpenGL for graphics, I suppose), which current eduke32 snapshots support and which is available here: [url=]http://connect.creativelabs.com/openal/Downloads/oalinst.zip[/url]. That should (hopefully) solve your sound glitch! :)

You need to delete the texture cache (texcache) folder each time you change the installation or video card.