Just been having a rummage through some saved mods and found one that adds fireworks to the game. Thing is that once the fireworks are launched the player is out of range of the detonation sound. What settings would need to be changed to be able to hear the explosion?

The sounds do play. But I can only hear them if I zoom up in the air and are stood next to the detonation.

Here's the file: http://morrowind.nexusmods.com/mods/12506

Interestingly in the videos linked the sound can be heard from a distance.

I believe there is no way to have further sound range than 255, also I believe that you can never hear sounds from a different cell than the one you are in. I have tested this quite a bit but now that I think about it I am no longer sure
You could just let the player emit the sounds, that might work well enough?