Recording a Comms session?

[No X In Nixon]

Evening all,

We're currently in the middle of a big performance that comes along every two years (kind of half variety show, half concert); and the other techs and myself have been trying to think of a way to set up our comms system that we can record it (one of them had the brilliant idea to overlay the comms chatter on the DVD of the performance as an 'extra').

However, as the comms packs are powered through the cabling that also carries the audio; we're very reluctant to plug the 'thru' into an input on a mixing desk for fear of blowing something up (which seems probable...).

Has anyone attempted to plug their comms system into a mixer to record, and if yes, did it work??? And if that's not possible, does anyone know of a way to record the comms without going as far as buying a complete new system?



Thanks a million

No X.

 

[Hughesie]

depending on your setup your base station might have a line out. I know concert intercomm ones do.

we thought of doing the same thing but never had anything to record it onto, plus some of our comments shouldn't be heard by the public.

I really *swear word* that cue

just an example

 

[loki]

Low Teck
A idea that might work, is simply plug another coms substation in, in a nice quite place, then turn it up full volume, and stick a mic near the speekers in the headphones and run the mic into a recording deck.

High Teck
I dont know if it exists, but you could make or buy a lead that plugs into the substations "Headphones" jack, and the other end would be XLR or RCA or somthing, then plug it into a recording station, it would elimonate the power issue, and would be neat, just dont know if the lead exists

 

[avare]

It can be easily done from the cables. However, without specifics of model, number of channels, two wire/single wire, it is impossible to give specific directions. The Handbook of Intercom Systems Engineering has the technical specs for several intercom wiring systems.

Andre

 

[No X In Nixon]

Thanks for those quick replys guys,

I'll check tomorrow what the model is - however as far as I know, it doesn't have a line out.


And as for the headphone to rca/xlr; that's not a bad idea... Could probably make one with not much effort... Again, I'll let you know how it goes!


Thanks again,

No X.

 

[waynehoskins]

The basic choices that will dictate how it's done:
- Clear-Com Party Line
- CC Matrix
- RTS TW Two-channel 3-wire
- RTS TW One-channel 3-wire
- Telex

Chances are it's a Clear-Com PL system: those are pretty standard in theatre. RTS is standard in television. Telex never fit in really well anywhere, and now has merged with RTS.

 

[DaveySimps]

+1 for the make your own cable concept. You should be able to find a wiring diagram for most modern systems that indicate the pinout of your spicific headset.

~Dave

 

[Van]

Agreed, make your own adapter cable, Just be sure to inform all parties that they will be being recorded, then after the production... destroy the cord so it can't be used again without fore-knowledge of the crew.

I had a Comms cnversation recorded behind my back once and it came back to bite me.

 

[Hughesie]

we had an ex crew, cast member steal a spare comms once. that wasn't fun

 

[Footer]

So is the Nixon name and recording conversations that usually are not recorded just a fluke? I had to ask...

 

[00AVD]

** Warning - commercial content **
What you want is something like I make.

 

[museav]

A headset out is an amplified signal and would have to be padded down for most recording devices, some of the older Clear-Com party line products showed the appropriate circuit in the manuals.

It has been a while since I did this but I recall that it was actually pretty easy to get unbalanced line level audio from a Clear-Com line, it might be something as simple as a capacitor and resistor inline. Contact Clear-Com and ask them, I believe they provided us a schematic for this.

 

[Chris15]

** Warning - commercial content **
What you want is something like I make.

IF you are doing what I think you are in that box, then it should also function, were one to add in an external attenuator, as an audio input module...

Assuming you have the old school 3 pin party line setup, then a simple cable will be all you need, again we need to know the system. The setup we get most of the time down here, and I think it's the clearcom one, has unbalanced audio on pin 2, 30 - 36 volts DC on pin 3. So what you can do is literally just make a split with a male and female XLR and a TS jack with the audio connected between pins 1 & 2. You can make it more rugged and stick in an iso transformer and you then get a setup that is functionally equivalent to that which David will sell you...

You can also take the route of using a beltpack, but then you have an extra box you need to find space for somewhere... We tend to have 4 pin XLRs for headsets down here, occasionally some 5 pin. The 4 pin is wired 1 Mic Ground, 2 Mic, 3 Ears common, 4 ears (left in 5 pin) and in 5 pin, pin 5 is ears right. I'm sure wiring that to something like a 40dB padded DI would work, but at the moment it's getting slightly late and I'm too tired to do the gain calculations...

Bottom line, with some more details we should be able to find you an answer to how to make it happen. As for the wisdom or otherwise of doing so, I think I'll let you sort that one out. I certainly would not be one to want to do it, unless you have a dual channel setup with just the show call on one channel and chat on the other.

 

[waynehoskins]

The setup we get most of the time down here, and I think it's the clearcom one, has unbalanced audio on pin 2, 30 - 36 volts DC on pin 3.

I think you've got that one backwards. Clear-Com PL has ground pin 1, 30VDC power pin 2, and party line audio pin 3.

RTS has ground pin 1, channel 1 (wet) pin 2, channel 2 (wet or dry, often dry) pin 3.

Both are unbalanced line-level-ish, RTS about 6 dB hotter than CC.

 

[No X In Nixon]

Hey Guys,

Thanks again for all the responses, they are greatly appreciated.

The comms system is a 'Jands' Ezicom E-200. It's a two channel, 3-Pin XLR system, but beyond that, I can't tell you much about it.

Does anyone know of this system or used it? It works fine for us, but if you add more than about 10 comms packs it starts to die (I'm assuming it starts to lose power...).


I can post pictures if you would like also;


Thanks again,

No X.

 

[Chris15]

A question to NoX, is it genuine Jands? Genuine Jands will more often than not have the case corners bent within months if not straight out of the box.

But never the less, viva the Aussie Comms.

Wayne is correct, my memory wasn't 100% at 1am... Jands Exicom is wired to the same standard. Pin 3 is line level audio. For one show, I've wired an adapter for an E400, the E200's 4 channel brother, to connect a radio mic receiver and IEM transmit to the comms bus. Clip a pair of beltapcks on and voila wireless comms... (Only works if you have that stuff spare...) Moral of teh story is taht if you take pin 3, you have utterly usable line level audio. I'd advise connect with the master turned off, whoever decided that the comms rings should start with Male connectors should be shot... Metal shelled XLRs can cause shorting which makes the fusible resistors etc internally go into protection mode... I speak from experience here...

As for loss of power with lots of beltpacks, that's not uncommon, and can be fixed by adding a booster power supply. If you have regular need for such a thing, I know I have a circuit lying around specifically for this and could probably email a scan of it to you... Basically what's happening is the power bus is dropping voltage because of the higher current through I2R losses etc and so you can't get as much juice out of it...

 

[FMEng]

If you do record comms, I suggest that you make sure that everyone on the system knows it is being recorded. In most states it is illegal to record a private conversation without permission.

For broadcasters, it's a violation of federal law to record without notice.

 

[derekleffew]

... For broadcasters, it's a violation of federal law to record without notice.

My TiVos and PVR are breaking the law?

 

[Chris15]

My TiVos and PVR are breaking the law?

Possibly copyright laws...

Definitely get consent. I still have to wonder if in time you might find that it's not as great an idea as you had originally thought...

 

[00AVD]

IF you are doing what I think you are in that box, then it should also function, were one to add in an external attenuator, as an audio input module...

Yes, it can be used as a line input when jumpered for line level mode. It works very nicely. I've not used that function myself yet but can see where it might be handy during rehearsals.

Our unit does contain a transformer. I'm a firm believer in avoiding potential problems with earth loops. It just makes it that much more bullet proof. If you have to listen to comms for hours you don't want extra hums and buzzes to drive you completely nuts!