Is the Evil Spirit of the Lord a Shadaim?

Adam from baltimore, maryland was wondering what doctor heyser thinks about david playing an instrument to help saul with the evil spirit of the lord. In first samuel 16, verse 14 23 would this be considered an old testament exorcism? Is the evil spirit shadaim? How does this correlate to psalm 91, world you about demon protection? i'm going to go to my demon's book here.