I currently have the Creative Sound Blaster X-Fi Titanium HD plugged in through RCA to the HIFIMAN - EF-2A Headphone Amp. I'm using the AKG Q701 headphones. Every now and again while playing games (haven't noticed it when listening to music) the headphones will either get really loud and sound like the speakers are blown, or get really quiet and grainy. It only happens for a few moments but it is really annoying. It doesn't seem to be limited to QTE's sometimes it happens during game-play. Any ideas what might be causing this?
Try not using the SoundBlaster & see if happens ...?...
this is most likely due to a bad wire, i had this issue when splitting my audio into a bus mixer, i had a bad wire and every now and again it would sound like a youtube video at 240p / go over the peramiters i have set for it.
replacing the wire fixed it for me, however try using built in audio to see if its the headset first, then test the sound blaster, and go from there.
testing is pretty simple, test everything for at least 1 full day of use to make sure that you don't mis anything.