I also have been having sound issues and believe, though I may be mistaken. that RO:HoS is using XNA/XAudio2 for sound management and render...
If true this is unfortunate for a multitude of reasons, not the least of which are no real hardware acceleration for those that have SOTA audio parts, poor sub-mixer and stream management, ugly gain ducking algorithms, and pooly fidelity -- just to name a few.
Where it gets really ugly is with integrated Audio/LOM solutions like Realtek (the lion's share) where Players will likely to see issues where sound effects net quality and verse visa... That I see these issues with SOTA audio parts from ASUS, Creative, and Auzentech, is especially worrisom...
Try reducing the number of audio "Max Channels" setting in the game to "8", if RO:HoS is in fact using XAudio2 this may help, and may also improve your network connection quality, stop or lat least reduce the audio stutter, and even improve emitter fidelity...