When Drag City announced that the super powers that are Nathan Bowles and Bill MacKay were joining forces, music fans rejoiced, knowing the result would be greater than the sum of its parts, which are already pretty great. The two musicians have many commonalities, including their versatility and adaptability to any musical situation, their respective breadth of work as solo performers, their acclaimed collaborative output, and a shared sensibility on genre and improvising. This delightful collaboration seemed as natural and self-evident as the sometimes charming, sometimes enigmatic songs and instrumentals on their album Keys, out April 9th. Keys draws on…