My off the wall prediction is that Daal is an Aluminum Misting and had a grenade (or more likely some new device) that was charged with Allomantic Aluminum.
Well he has perfect pitch so my guess would be that he's using the rhythms to manipulate it. I wonder if the other shards have rhythms of their own, that might be a method of changing investiture from one form to another.
I wonder if the logic fabrials can have their pulse patterned to match up with the Rhythms. I imagine that would be a very effective way to scale up fabrial design and specifically this chapter's newly introduced farming method.