Okay, I've been playing KMod for some time now with 3D Sound enabled. I love the reverb that you get when it's turned on. However, when you step out into an open space from a closed in space when a sound is playing, the reverb drops off instantaneously as well. It's only a VERY minor annoyance, but it just doesn't seem very realistic.
Does Doomsday only reverb sounds when you are in a sector with a non-sky ceiling? It sounds to me like it does. I think it should let the reverb finish out if a sound is playing as you step from a non-sky ceiling sector into a sky'd one.
By the way, those with just onboard audio on their computers, leave 16-bit sound interpolation off when playing with 3D Sound turned on. It helps out tremendously in keeping the game from 'hiccuping' while playing with 3D Sound. At least it does on the comp I usually use to play KMod.
God's mercy and love for us all is endless and cannot be measured.