There are (at least) six different compression formats for .wav files, including the option to have them as mono or stereo. Some of those compression formats won't work at all with 3DGS.
If you have the SoundBlaster software, it frequently comes with a utility called "Wave Studio". That utility has the capability to save in mono, stereo, and the different compression formats.
To the best of my knowledge, 3DGS has the ability to play stereo, as well as "surround sound" to give you position information as to where the sound is coming from.

Hope this helps!