config left - right speakers

[jmwismer]

... drag and dropped my two Phantoms in the left and right slots for speakers, etc...

I would say that you answered your own question, well almost.  

At the point that Spark requests that you drag and drop each Phantom into a position, the selected Phantom emits a ping and “flaps” the bass cones to identify which one you are moving.

I’ll put your oversight down to the excitement you had in wanting to listen to them.  

Oh! and, painfully, you will have to perform another setup. There is no other way to re-assign.

thank you alandbush for your precise and comprehensive answer! I missed the ping and flaps indeed...