Thanks for all the input everyone. We have had a kind but firm discussion with him about division of labor in the worship ministry. It has also been communicated that he, by the way, is just plain wrong in his theory.
I am glad to report that all of the sensible recommendations that have been put forward in relation to this post are SOP for our group.
Incidently, he's a drummer. I haven't worked with him directly but I'm quite certain he would not be open the suggestion that he is setting up his kit wrong.