Wedge (Comms)

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Wedge is the analog studio comms system used at YSTV. Camera ops, floor managers and presenters get a belt pack connected to a headset, which is then linked back to a director box in the control room; all over 3-pin XLR cable. It is a party line system, so everyone on a director box channel can hear everyone else on that channel, and uses balanced signalling with integrated power, so should be reasonably tolerant to nearby electrical noise.

Belt Packs

Each belt pack has a pair of XLR connectors on one end, headphone connectors and a talk switch on the other end and a volume control down one side. Headphones and microphones use a standard 3.5mm jack, so PC headsets and earbuds will work well.

The jack nearest the mute switch is for a microphone, any kind of PC headset microphone will do the job, and the switch next to it will enable talk when pushed towards the microphone connector. The other jack takes headphones, either stereo or mono, and then clockwise on the volume knob increases volume. Be warned that if the volume is too loud and your microphone picks up your headphones, very loud feedback rings across the entire system, so be a little bit careful.

The XLR connectors are linked together, so either can be used and belt packs can be chained together if needed (although often it will be easier to split it with a squid and use an umbilical). In theory they should also tolerate accidental connection to phantom power without too much trouble.


Squids are a handful of XLR connectors all linked up inside a box, effectively splitting one comms line into several; usually they are a small metal box with connectors on short leads hanging off, hence the name. There are no electronics inside, so any connector can be connected either to a beltpack or the director box (but don't plug two director channels into each other!)

Director Box

The director box is effectively five belt packs linked together, so the director can talk/listen to any of the five channels. This box also injects power into the system so beltpacks have to be connected to it in order to work.

Along the front panel are a pair of 3.5mm jacks, a volume knob and lots of switches. The top row of switches controls which channel to talk to, and the top 3.5mm jack is the microphone input. The additional switch left of the jack will enable the microphone when down, and channel 5 (far right) has a push switch instead of a toggle. On the bottom switches control which channel to listen to and the jack is for headphones. Down is on for all the switches.

For the connectors on the back, the far left XLR connector (closest to power) corresponds to channel 1 (far left) on the front.

Sound Desk Injection

One beltpack, which should be labelled as "Desk Injector", can be used to send the presenters' microphones from the sound desk into the director's headset. Don't try and go the other way from comms into the desk, as the comms headset ground is 6V above earth, which is safe but might upset the desk without ground lift.

The injector beltpack has a three-position talk switch; down is talk using a microphone as normal, the centre is mute and then up (away from the connector) disconnects the ring bias voltage for connection to the desk. To use it, connect an aux/group to the beltpack and send the presenters' mics to that aux pre-fade, then plug headphones into the beltpack as well and drop the output level on the desk until the director is happy.


See also:

Comms was tested in May 2014 to see how far it would work. Turns out, very far. An comms line was run from YSTV to URY's studios across the lake - using approximately 275m of cable. It was a bit quiet, but otherwise worked fine.