Com Squawker

Do you ever use a small (powered) monitor and mic pair at FOH and MONs to talk back and forth? Usually see these at festivals, allows you to not have to wear com and keeps your hands free while you converse back and forth between MONs and FOH regarding patch or whatever.



Have you ever had that situation where the monitor tech or FOH tech won't answer his com even though you've been calling him for hours?



Well, this circuit I designed allows you to both those things, interfaced with your com. If you already have com between FOH and MONs, using this circuit, you just add a some powered computer speakers (or a powered monitor) to it.



The way it works is that when you press AND HOLD the call button on the com, it activates the remote speaker so you can talk (or YELL) at the tech at the other end. The speaker is only active when you are holding the call button, and your local speaker is not active (so you don't get feedback)



Seems to work in testing, but since I'm working in theatres now and have a monitor tech who I've never needed to yell at, I don't actually use it. I think it would be very handy (and cheap) if you're handy with a little simple electronics. Somebody more knowledgeable than I could probably do this more elegantly with a transistor circuit in place of the relay, but I have piles of these 24v relays I used to make a pile of com strobes, so there you go.



The output is meant for connecting to (stereo) computer speakers, using an 1/8'' TRS connector. If you're using something professional, ground pin 3 instead of connecting it to the signal.



Set R6 at max resistance.

Adjust R1 so the wiper is grounded.

While holding call on the remote beltpack, adjust R6 until the relay trips and the LED lights.

Release call on the remote beltpack and press and hold call on the local beltpack.

Adjust R1 until the relay does not trip.

Tweak as necessary so that the remote call always trips the relay and the local call does not.



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