So, here it goes...

Go to folder Documents inside "My Documents":
.\Documents\My Games\KillingFloor2\KFGame\Config

Open file "KFEngine.ini" with Notepad and use Ctrl+F for searching. Search for: [XAudio2.XAudio2Device]

Change these values as described below:

MaxChannels=32
CommonAudioPoolSize=0

MaxChannels dictates to the game how many audio channels it uses to play sounds. 32 works on majority of even crap soundcards but some can do more. My Sound Blaster Z supports up to 128 channels and I've tested 96 which works perfectly fine (120 causes weird static noise). The sound becomes a lot richer since more sounds can be played at once without overlapping others, potentially resolving sound skipping. This number is usually 16, 32, 48, 64 or 96. Try it and see if it makes any difference. Using values below default value 32 is only recommended if nothing else fixes the issues.

CommonAudioPoolSize is an audio buffer to my knowledge and keeps audio pre-buffered in memory so it is always ready for instant playback without any delay. Default is 0, but increasing it to 32, 64, 128, 256 or even potentially more should help a bit. I'm using 256 and it's working perfectly fine for me. This should potentially fix audio stuttering issues.

Save the document and run the game. Let me know if it helps on any of those problems in real-world conditions.