All sound drops to a much quieter level, I have to restart client to get any volume back. Can be hours or every 3 minutes. I'll try the /reloadui and see if it works.
I too have this issue, i thought it might be attributed to lag or packet loss, but when it happens my latency is a solid 50ms and show 0 loss. I have no clue as to what could be causing it.
I've had all of these same problems and have tried the same solutions others have posted here. It happens but rarely on my desktop but several times per day on my laptop, both have the most up to date drivers and exhibit the same problem no matter which sound sources I enable and disable.
Semi retired from the trading aspects of the game.
I have had this happen to me as well, its rare but seems to happen if i have been in game for awhile. For me, its just npc conversations stop, I just cant hear them but can hear everything else. In some case I wont hear anything at the start but then it will come back mid way through a conversation and stay for awhile before it drops again.
I noticed it seems to be triggered if you click to fast past a conversation, it can cut the npc audio out. Zoning to another zone fixes it, I have found.