I have read that professional theaters make custom halo mics for the actors. What materials are used?
1) A miniature omnidirectional lapel microphone. This type of mic is typically offered in different colors to match skin tones.
2) Elastic cord. Available at fabric stores in a variety of colors.
Elastic cord is cut to fit around the actor's head, above the forehead The mic cable is secured to cord using a simple knot. The two ends of the elastic cord are tied together to form a circle or "halo." The miniature mic is positioned above the actor's nose, with the mic grill pointed downward. The mic cable is held to the actor's hair using toupee clips.
Thanks to James Savage, head of audio for Chicago Shakespeare Theater, for this tip.