Sure it's possible. Since auto-attack mods are essentially custom windows to begin with, you don't have to modify one to do this. Just make a second custom window... could be one that isn't even visible if all you want is sound from it.
You'd be limited to the 30-40 sounds that the UI has access to. Unless you can use the override method described by the UIBuilder doc to add your own that do not exist already.
I'd try making a text changed event for Self.TimeSinceAutoAttack, working out the logic for that... then use the ShowSound page attribute on some custom Page element that you show via-script.