Communication for live concert

[Bouncing Account needs new email address]

There are lots of wireless headsets out there but for reliability…

You can use regular headset TELEPHONES wired together.
You can even use Cordless Phones for this, but there’s always the danger that
there will be interference.

Its a simple matter to just connect as many standard telephones as you want (use standard telepnone cables to connect them) and you’ll have full duplex talk. (If you get headsets with “mute” buttons, your camera guys won’t be “breathing” in your ear the whole time.)

Buy phone cables, splitters and junction boxes at Radio Shack, Wal-Mart or (my favorate) the DOLLAR STORE.

You can power this with two 12-volt lantern batteries (in series to get 24v DC).
You’d connect the batteries right accross the red and green telephone lines.
Batteries work for HOURS.

You can use an AC-powered 24v DC Power Supply, but you need to “choke” (filter coil) the DC output so the capacitors in the power supply don’t “filter out” your audio.

You can buy cheap headset telephones ($4-$5 each) at discount stores (or Used for next-to-nothing.)

We use these telephone systems for all kinds of live events.

[Kurt Schuette]

Thanks for the idea. That’s an interesting system. You wouldn’t happen to have a schmatic for this setup, would you?

Thanks,
Kurt

[Bouncing Account needs new email address]

There’s no real need for a schematic.
All the telephones would be plugged into the SAME “line” (its just regular phone cord with the 4-pin plugs.)

You can have as many phones as you like and as much cable as you need. Just connect it all together with those little “Y” adapters that you use for adding phones, fax machines and answering machines to a wall connector. You can run all the lines to one spot and make all the connections there, or you can “hop-scotch” each one from the next… no difference at all.

For the battery, you want about 24v DC, so you could buy two 12v “LANTERN Batteries” (rechargeable would make sense) and hook them in SERIES to get 24v.

At the battery connection, buy one those little square telephone “wall plugs” (with the 4-pin jack and the 4 wires inside).

Typically, connect the PLUS side of the battery to the RED wire, and NEGATIVE of the battery to the GREEN wire and plug it into the same line as all the phone units are hooked to.

Any phone that is on this line will talk/listen to all the others.
Telephones are simple to connect.

And since ANY phone will work this way, as I said, you COULD connect any CORDLESS phone and try that, if you need to.

We just did a 3-day shoot with 4 cordless phones, one on each camera op.
We had to remember to re-charge the phones each night, but they worked just fine.
But, I’m still a big believer in WIRED communcation when its practical… it WORKS!

[Douglas Villalba]

This is what I use https://www.eartec.com/td904pro.html

Douglas Villalba
https://www.dvtvproductions.com
dvillalba@dvtvproductions.com

[Kurt Schuette]

That sounds like a cool set-up. I just might give that a try. Thanks!

-Kurt

[Kurt Schuette]

One more quick question. I am not familiar with a filter choke. Where can I get one of these?

Thanks,
Kurt

[Bouncing Account needs new email address]

A choke is a coil (like the primary or secondary of a transformer).

The particular property of a choke is that it passes DC but will not pass AC.
(The opposite of a capacitor, which passes AC but not DC.)

In this telephone system, you can use a 12v or better still, a 24v DC power supply instead of a battery, but you must send the current to the phone line through a CHOKE (which will pass the DC to the line) so the AC (your voice audio is AC) will not pass back through the choke and get “filtered out” by the capacitors in the power supply.

You can use just about any transformer winding that is not too LONG in wire-length (so that it resists too much voltage) but is also heavy enough (in wire gauge) to carry the current needed (about an amp is fine).

Here’s a transformer from Radio Shack that should work as a choke for this purpose (there are others):

https://www.radioshack.com/product/index.jsp?productId=2102700&cp=&kw=transformer&parentPage=search

Just connect the secondary winding in series with the positive (+) from the power supply.
(Connect the + from your DC supply to one of the red leads and connect the other red lead to your Red phone line.)

[Doug Graham]

Here’s a couple more from the ‘Shack:

https://www.radioshack.com/search/index.jsp?kwCatId=2032058&kw=choke&kw=choke

Regards,
Doug Graham

[Bouncing Account needs new email address]

[Doug Graham] “Here’s a couple more from the ‘Shack:”

I’ve fear I’ve spent too much time choking on this “choke” stuff already 😉

But… the 3 chokes listed at the link you posted are for filtering “RF” (radio frequency) and (in the second one listed) very LOW current capacity, for wireless tuner applications.

The kind of choke I’m talking about filters “AF” (Audio Frequency, in the human hearing range) and carries (at least) one Amp of current, for power supply purposes.

Now, I’m off… chokin’ and jokin’ !

[Doug Graham]

Yep…my bad.

Regards,
Doug Graham