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[Peter Kowalczyk]

Hey Folks,

A new bar is installing a small performance stage, and we're planning a 2" pipe a few feet out from the downstage edge for a couple of basic LED wash lights.  While most of the time, they'll be set to some static or standalone mode, we'd like to install provisions for DMX control for future use and / or future fixtures. 

The electricians will be installing all sorts of structural wiring, and I've recommended that we run some DMX from the stage and / or FOH position to the truss. 

Would you recommend using 3-pin or 5-pin connectors on the wall plates for these in-wall runs? 

Thanks!

[Drew Kirkland]

I would probably go with 5pin XLR which is industry standard and will differentiate the lighting from sound. 4 + 5 are not always used but with some systems they provide feedback to the control system which can identify fixtures that are suitably equipped. Pin 1 Screen Pin 2 Data- Pin 3 Data +

[duane massey]

Personally, if it is a small bar, I'd just use 3-pin and be happy IF that is what the fixtures use.

[Lyle Williams]

All basic and cheap DMX lights are three pin.

[John Fruits]

It will depend on which fixtures you get.  It used to be that the DJ grade cheaper fixtures were 3 pin and the Pro grade fixtures were 5 pin. (Well except for High End Systems for a while.)  Now a lot of fixtures have both 3 and 5 pin connectors. 
Whichever you go with, make sure they use DMX cable, not mic cable.  The current RDM (Remote Device Management protocol is on pins 2 and 3 along with the DMX signal.
One other thing to keep an eye on, pipe sizes.  when you say 2 inch pipe, you probably mean 1 and 1/2 inch Schedule 40 black pipe. 
http://www.mcnichols.com/?pageCode=pipedims
If you say 2 inch pipe, and the installer listens you will get pipe which is 2.375 inches in diameter which MIGHT work with C-clamps but not with the usual truss clamps.  I am aware with several installations in which 1 and 1/2 inch Schedule 40 was speced but 1 and 1/4 inch pipe was installed.  Some C-clamps won't work and most of the truss clamps won't either. 

[Nathan Riddle]

It will depend on which fixtures you get.  It used to be that the DJ grade cheaper fixtures were 3 pin and the Pro grade fixtures were 5 pin. (Well except for High End Systems for a while.)  Now a lot of fixtures have both 3 and 5 pin connectors. 
Whichever you go with, make sure they use DMX cable, not mic cable.  The current RDM (Remote Device Management protocol is on pins 2 and 3 along with the DMX signal.
One other thing to keep an eye on, pipe sizes.  when you say 2 inch pipe, you probably mean 1 and 1/2 inch Schedule 40 black pipe. 
http://www.mcnichols.com/?pageCode=pipedims
If you say 2 inch pipe, and the installer listens you will get pipe which is 2.375 inches in diameter which MIGHT work with C-clamps but not with the usual truss clamps.  I am aware with several installations in which 1 and 1/2 inch Schedule 40 was speced but 1 and 1/4 inch pipe was installed.  Some C-clamps won't work and most of the truss clamps won't either.

This ^^ My goodness, I have specc'd 2" pipe and they get me 1.42" stuff; It is beyond annoying.


Also, 3-pin. Unless it is a theater, or somewhere where they are ALWAYS going to spend the money on pro grade fixtures I wouldn't waste my time with 5-pin.

[Rick Powell]

I'd get 3-pin fixtures and use 3-pin DMX wiring. And install a little controller so at least you'd have convenient, basic control over the installed lights that doesn't involve standing on a step ladder and pushing a bunch of buttons on each individual light to change the colors. The odds are probably 9 to 1 that whatever local act comes in with a supplemental controller and lights, it will be 3-pin.

If anyone comes in with an elaborate 5-pin DMX controller and lighting rig on a one nighter, they are likely to just work around what you already have anyway, or use one of those 5-to-3 adapter cords or barrels in the rare chance they'd want to incorporate the house lights.

[Peter Kowalczyk]

Thanks All,

3-pin it is then; whatever fixtures we get will almost certainly be at the low-budget end of the spectrum.  I'll definitely clarify the difference between 110 ohm STP for DMX and basic STP for analog audio as well.

Thanks for the clarification on pipe OD versus nominal size - thats a difference that makes a difference.  (Yes, I'm an audio guy stepping out of his league here...)

Cheers!

[John Fruits]

Just to confuse things more, the DMX protocol calls for a single pair for 3 pin and two twisted pairs for 5 pin.  BUT if you check the manuals for most brands of lights on the 5 pin connectors, pins 4 and 5 aren't connected internally.  The higher quality 5 pin cables follow the standard with two twisted pairs but the less expensive brands use a single twisted pair with pins 4 and 5 not connected. 
One other thing, in your post about relays for power for active speakers, you should do the same thing for your LED lights.  One popular item for doing this is the ETC ColorSource relay.

[Erik Jerde]

If cable is being purchased specifically for the dmx then put in 2 pair.  The cost difference is negligible and then you're prepared for whatever comes your way.  I'd terminate it to 5 pin and then use a 5-3 adapter if necessary.  Lots of lighting desks will output 2 universes on one 5 pin making it easy to get both universes to stage with one cable.  It sounds like you'll never need 2 universes but with the way fixture address counts have gone you'll never know.

Anyways, I'd go big.  It's cheap and easy and you won't ever regret it.

[ProSoundWeb Community]