Not exactly the answer you might want, but I would recommend playing W7 DOS version for better overall experience. There you can definitely mute the sound.

Did that come with the GOG.com version, and if so, how do I access it?

...Never mind, I forgot that it was in the bonus stuff. I've installed it, now to see if it will work.

...Neither Wiz7 DOS or Wiz 6 are working. I get the DOSBox console window for both, then the console window closes without any other output. On looking at the shortcuts that start the programs, I noticed that two configuration files are being loaded for each game. Not sure if this is normal. Here's the Wiz7 DOS shortcut line:

"C:\GOG_installs\Wizardry 7\DOSBOX\DOSBox.exe" -conf "..\dosboxWizardry7.conf" -conf "..\dosboxWizardry7_single.conf" -noconsole -c exit

Any ideas as to why they may not be working?

Start Menu - GOG - Wizardry - Graphic Mode Setup. Change Graphic mode to openglnb, opengl or ddraw, retrying after each change. Alternatively, directly edit dosboxWizardry7.conf.

I've got the following in my Windows shortcut:
"D:\Games\Wizardry 7\DOSBOX\DOSBox.exe" -conf "..\dosboxWizardry7.conf" -conf "..\dosboxWizardry7_single.conf" -noconsole -c exit

The game is installed at:
D:\Games\Wizardry 7\DSAVANT

It works without any problems.
Window 7 Ultimate, 64 bit

Looks like having two config files is ok - they apparently executed one after another.
Here is the contents of the second one (I would assume yours have the same):

[autoexec]
# Lines in this section will be run at startup.

@ECHO OFF
mount C ".."
c:
cd DSAVANT
cls
ds.exe
exit

Sorry about the delay. I've been playing Wiz 7 DOS in my own DOSBOX installation (I have all the memory settings cranked in there). It works, so I figure 6 will work too. Thanks for trying, though. I never found the DOSBox config files in the Wiz 6 or 7 directories, though, and Wiz 7 Gold only has Launch.exe. If there were such files in there, they must have gotten deleted during the install process. Anyway, thanks again. I'd forgotten how hard the Wizardry series is until I started playing Wiz 7 DOS. :)

Cool, don't forget to take a look at the *Cosmic Forge* editor's patches.
There are a few that can enhance the game-play a lot.

Actually, the game is installed wherever you tell the GOG installer to put it...;) Yep, and Windows 10 x64, too...;) Yes, but you can make a custom *.conf file to use with svn-daum dosbox (64-bits) if you want...that's what I did...only takes one, but GOG likes to modularize their dosbox.conf files for their own internal reasons, I guess. Some of their DOS games use three .conf files... C ".." means "For this DOSBOX game, make the folder where Wiz7 is installed the C:\ drive" AFAIK...;)