I was recently contacted by one of my Twitter followers who was interested in our school's media production facility. He was in the process of desiging a similar project at his school, and I assured him that I would help out in any way possible.
Sometime last week he contacted me once again and informed me that most of his equipment was ordered, but that he was missing one small piece of the studio design. He needed a communication system for his facility so that the director could be in contact with everyone (camera people, audio engineer etc.) during the production. Our school, Toledo Central Catholic, uses a TELEX system, something I highly recommend, but it cost us over $2000.00.
He asked me if I would be willing to come up with an economical way of creating a such a communication system. I pondered this for a couple of hours. Wireless walkie-talkies would work, but are limited in that they do not do full duplex communication and usually require push-to-talk.
In the end I came up with something that I hope will be a viable, full duplex, yet inexpensive solution. It revolves around using a standard mixing board as the basis for the communication system. A Mackie 1202 VLZ is one example, and many other inexpensive mixers would probably work just fine.
Next one would need to buy 5 (or more) of these inexpensive headsets:
http://www.bhphotovideo.com/c/product/689922-REG/Cyber_Acoustics_AC_101_AC_101_MONAURAL_HEADSET_MIC.html (or better headsets)
And 5 of these headset/laptop adapters:
http://www.bhphotovideo.com/c/product/740841-REG/Woodees_VOIPAD35_VoIP_Laptop_Adaptor.html
Some headphone jack splitters:
http://www.bhphotovideo.com/c/product/252296-REG/Hosa_Technology_YMP_234_Stereo_1_4_Male_to.html
and miniplug to 1/4 inch adapters:
http://www.bhphotovideo.com/c/product/202553-REG/Hosa_Technology_GPM_103_GPM103_Stereo_Mini_to.html
Next, connect the headphone audio jacks to the mixer headphone jack (with splitters and extender cables) of the mixing board. Connect the mic jacks using extender cables as well as 1/8 inch to 1/4 inch adapters to the audio inputs on the mixer.
1/8 inch extender cables can be found here:
http://www.radioshack.com/product/index.jsp?productId=2102968#
Technically, everyone should all be able to communicate in full duplex at that point. The director could mute specific audio inputs so that everyone is forced to hear only the director, or she/he can unmute if a question needs to be asked of one of the crew. Volume for all headsets would be controlled by the headphone volume control on the mixer. All this for around $400.00. A schematic is here in PDF format.
I'm interested in how well this works if anyone puts it together. Please make suggestions on how to improve this project in the comment section of this blog post.
CH