Ok, I'm having the same problem, and even when I do what you say, I still can't hear the gun fire sound in-game. I have a MG42 mod that I was editting the stats of with GECK so the gun was more like the real deal. I got to the art and sounds section, and it already had custom sound effects to start with, but they didn't satisfy me. I looked up what I needed to do to add my own, and I learned that I needed a .wav file, so I downloaded the audio from a Youtube video with high quality sound of the MG3 firing from Battlefield: Bad Company 2. I editted the audio in Windows Movie Maker to where there was only one round firing like it needs to be for using in GECK. After that, I converted the file from .wma to .wav. I put my own file in the sound/fx/wpn folder and deleted the original audio file that came with the mod. Finally, I opened GECK, clicked miscellaneous, then sound. I created my own form called WPNMaschinengewehr42Fire and selected my audio file for the sound to be used. For some reason, when I click play to preview the sound, it doesn't play anything. I didn't change any of the other things below while creating the form, and I don't know if that's the problem. Then, I created the form, found the gun, chose to edit the gun, went to the art and sound section, changed both of the two gun fire sound effect options to my custom sound, then I OK'd it and saved the .esp. Now here's where I get mad. I made sure the .esp was selected and ready to use in Fallout 3. Then when I find the gun in-game, I whip it out of my pants, and BAM! NO SOUND! All of the sound besides the gun fire is completely fine and still working (Ex.: Reloading, pickup, drop, equip, unequip). If you somehow help me fix this, you'll probably be my best online friend of all time! Oh, and by the way, I tried the same thing with other guns, and none of them worked correctly either. I don't know what the deal is, but I think GECK hates me pretty hardcore.
