If you’re still using these, you might consider a upgrade. Photo by Joe Haupt CC by S.A-2.0
Digital communication can:
The Titan Radio 4X Digital is a great comm for your theatre. Wireless is fantastic for historical buildings, touring groups, and it’s good for the budget (no cable to purchase OR run). Some of our favorite features include 32 channels for optimal privacy/organization, a nearly 11 hour battery life, and an IP54 rating for protection against dust ingress and protected against splash from any direction. While we aren’t planning on swimming with these radios, a terrible idea, it’s good to know an errant sprinkle is unlikely to damage the radio. The accessory retainer screw is very neat as well to keep headsets from falling out with a small knock. It’s not necessary to gaff tape the headset to the radio for your clumsier crew. As always if you need some help deciding which radio communication system is right for your space, give us a call or drop us a line. If any one of us at StageSpot hasn’t used it ourselves, we know someone who has. 
