Thats easy 

1st you need to create a mod in the games mod dir. Then you need to convert the player entities you want to modify from the game or use the reference files and place them in the mods GameInfo folder. Then copy all the sound references from PlayerPsi.entity (Advent) to PlayerPhase.entity (Vasari). Here is the 1st Vasari snd I see in the entity...

gameEventData
         GameEventSound:AllianceCeaseFireBroken "EVENTPHASE_ALLIANCECEASEFIREBROKEN"

Now you want to look for GameEventSound:AllianceCeaseFireBroken in the advents entity and copy the sound used in the quotes to the vasari entity

Notepad++ has a great compare feature that makes this a breeze. Post back with any issues or more questions. Reference Files and more modding tools at http://soase.weebly.com/modding-tools.html