At first, sorry for my bad English (hope not as bad to be difficult to understand). I'm using a translated version of Construction Set, so many names could be different than in original.
Well, I have found in Magic Effects space for new spell. This is calles sEffectExtraSpell. I change it name, school, base cost etc. but i can't do this spell to be for "Myself". It is only possible to be for "Target" and "Touch".
I have tried to use this a bit, and I couldn't get it to use for self. It must be coded for offense/attack. If you script you can test for if the effect has hit an NPC or creature; so you could script an effect with it, and you might be able to script a test for sound with a new sound for it - (but I didn't try that). If you want to try this with scripts I would give the advice to look at some of the scripted spell mods available.
but i can't do this spell to be for "Myself". It is only possible to be for "Target" and "Touch".
It must be coded for offense/attack.
Fire damage is meant for attacking but you can cast it to myself anyway.
But yeah, scripting is the way to do it. However, if you're making a mod, better make a normal spell and script an effect to the ID of that spell, otherwise it will conflict with all the mods that make use of that extra spell effect.