.wav sound effect woes.

I’m working on giving a couple NPC’s I downloaded some voice, but it’s partially not working:

I downloaded some pre-recorded sound effects already made for Gmod for the specific character I’m testing (Solid Snake), but I personally gathered more to spice up the variance a little.

I’m using a set up from ‘Dan’s 100% homemade NPC’s’ pack, with altered file paths for Solid Snake.

Only the pre-made Gmod clips I downloaded work, but the ones I tried to cut and export myself don’t.

In the lua file, it randomly generates one of six idle sounds, but it only plays the two I didn’t make.

What do I need to do in order to get these WAV files working in Gmod?

TL;DR: What are the specifications for .wav files in order to get them working in Gmod?

16-bit 44KHz, stereo wave I believe.