This is something that has been a problem for many years, but I am just now remembering to log a bug.
In Suneal Thorpe when my PC enters any of the merchant's buildings something happens to the sound in my NWN client, such that it starts screeching. It does this for about 30 seconds and then all sound stops. Once the problem is triggered, it does this at every transition (door or area). Enter a door, screech, no sound. Exit a door, screech, no sound. Transition out of Suneal Thorpe, screech, no sound. This problem does not stop until I exit the NWN client and start over. I have not experienced this in any other location on Avlis.
I am using the Linux NWN client, in case that matters.