What is this"addressing" you speak of?

Techies sometimes speak in code.  It can be intimidating for sure.  It is "DMX" this and "XLR" that and "digital" and "analog" and "address" and "universe" and "5-pin versus 3-pin".  ACK!  What is a non-techie to do?

Well, here you go.  We will break the code for you.  All of those words have to do with how dimmers or fixtures talk to the console.  It is all about control language.

Way back in the day when we just had dimmers and consoles, there was no universal language.  If you bought dimmers from one company you had to buy a console from them too or they wouldn't communicate with each other.  In the mid-80s people started thinking that it was silly to have so many different control languages and gosh, wouldn't it be cool if everything would talk to everything else?  So the engineering commission of the United States Institute of Theater Technology (the body that governs technical theater standards) developed DMX 512 (digital multiplex with 512 pieces of information).  Finally there was an approved standard for the control language between dimmers and console.

So how does it work?  Before DMX, everything was analog.  Analog dimmers had to run a cable from each dimmer to the console.  That's a lot of cables.  DMX512 uses one cable and sends little packets of information down that cable.  The trick is that each packet of information is directed to a specific address.  Your dimmers all have an address.  They ignore the directions flying down the cable until they hear their specific address.  They they perk up and do whatever the next direction is.

It works just like the post office.  Under the analog system each house would have had their own mail carrier.  Under DMX protocol each house has an address and only gets mail sent to that address.

So with dimmers, you don't have to worry about much usually.  Most school theaters are set up where the circuit/dimmer/address are all the same.  Dimmer one is address one and so forth.  Where it gets tricky is when you add LEDs and moving lights to the mix.  LEDs and moving lights are not plugged into dimmers (or they shouldn't be.  Doing so will pretty much fry them.).  You have to set the address on LEDs and moving lights.  This isn't hard.  Just figure out what your last dimmer number is (including house light dimmers) and start from there.  So if you have 24 dimmers in your dimmer rack and then another 6 dimmers in your house lighting system, you have used up your first 30 addresses and would start your LEDs/moving lights with 31.  I'm lazy though and want the math to be easier, so I would probably start with 35 or 40.  I might even start with 100 depending on how many LEDs and movers I was using.  Skipping address doesn't matter.  Each fixture sets them a little differently.  Make sure to check your manual on which buttons to push to get that sucker addressed.

Keep in mind that LEDs and moving lights need more than one address.  They need an address for everything that they can do.  So an RGBW LED would need anywhere from 4 to 9 addresses and a moving light can take several dozen.  Your fixture manual will give you the DMX options for that fixture and will tell you what each address does.  The new fancy schmancy consoles will take care of this for you.  You tell the new consoles what the starting number is and what kind of fixture you are using and it will automatically take as many addresses as the unit needs to function.  The other weirdness is that you sometimes have to pick a "personality".  Sometimes there are options about how many functions you want to use on each light.  Go read the manual and pick which one works for you.  As long as you use the same personality on the fixture and in your console you should be fine.

But what is this "universe" you speak of?  Have we gone all Star Trekkie on you?  Nope, although we are huge Trekkie fans.  A universe simply refers to a line of DMX.  A DMX cable will only send info to 512 addresses.  Not a problem when we first started with this stuff, but now we use piles of LEDs and moving lights that just suck up DMX addresses.  So we started adding more lines of DMX.  Each line is called a universe and is numbered accordingly.  First universe is DMX 1-512.  Second universe is 513 to 1023.  Third universe is 1024 to 1535 and so forth.

DMX 512 cable has five pins inside.  Thus it is sometimes called 5 pin cable.  There is also three pin DMX cable that will work for certain gear.  Some fixtures need a DMX specific three pin XLR cable.  There is also 3 pin microphone cable, but it isn't the same thing.  While it might work okay some of the time, the cable is actually different and will not always work the same way.  Certain LEDs absolutely cannot run off of mic cable, so you are well served to buy the real thing.

So there you have it in a nutshell.  DMX isn't as scary as you thought.  Bring on the LEDs now!