Proper communication and direction will go a long way with any of our volunteer ministers. Love them, praise them, and help them to be what God has called them to be and we will all benefit...so will the people of the church as they gather to worship from week to week. Tension and conflict can be avoided with proper directed communication. Work together as a team and watch your people flourish and your ministry flourish. Ministry is people, and the more you have working with you, the more ministry you can do.
Finally, I know there are cases where volunteers take their ministries" into their own hands and don't want to be told, by anyone, how to do it. In those cases you need to be firm and exacting in your expectations and the roles you both play. In these cases it is sometimes better to not a have a sound tech than to have an arrogant submissive one. Remember, you are responsible for the sound of the church. You are responsible for the attitude and the spirit of the team. As a friend use to say, "there is no "I" in team. These are the times when getting tough is needed for the sake of the whole group and ministry. Hopefully those times are rare. Learn to love the people you work for and with, communicate what them what you expect and need and your ministries will be more productive and joyful.