The part everyone skips
DMX lighting explained, without the jargon
DMX is one long list of 512 numbers sent down a cable, and every fixture is told which slot in that list to start reading from. Almost every mystery fault on a small rig is two fixtures told to read from the same slot. Once addressing clicks, patching stops being frightening and becomes arithmetic.
The order to do it in
Step 1
Picture one universe as 512 numbered slots, sent down the cable many times a second.
Step 2
Each fixture is given a start address, the slot it begins reading from, and it reads as many slots as its mode needs.
Step 3
Check the footprint before you place anything. A moving head in an extended mode can eat thirty-two slots where a simple LED par eats four.
Step 4
Place fixtures so no two ranges overlap. Two lights reading the same slots is why one answers a command meant for the other.
Step 5
When you run out of room, you add a universe rather than squeezing. Nothing may straddle the end of one.
Drills that practise this
Patch the Rig
Read the Beam
The Desk
Do it on your own rig
Put your fixtures in and get start addresses that leave room to change your mind, plus the real current draw so you know how many circuits you need. Free, and it needs no account.
Questions
What happens if two fixtures share an address?
They both obey the same commands, so they move and change colour together whether you meant it or not. It is the most common fault on a small rig and it is a patch problem, not a broken fixture.
What is a fixture mode and why does it matter?
Most fixtures offer several channel layouts. A compact mode saves address space and gives you fewer controls; an extended mode gives finer control, often 16-bit movement, and costs far more slots. Choosing is a real budget decision once a universe starts filling up.
Do I need a second universe?
Only when 512 slots run out, which happens faster than people expect once movers are involved. A rig of simple LED pars will never get close.
More lighting guides
Stage lighting setup, in the order that actually works
Work out the order to aim and level a stage so it looks right from the seats and on camera.
How to program a light show
Understand how a programmed show is built and why edits to one cue leak into later ones.
Stage lighting for small venues and bars
Make a small handful of fixtures in a low room look deliberate rather than thrown at the stage.
How to light a band
Know where to put light on a band so it looks like a show rather than a lit rehearsal.
Stage lighting colours and what they actually do
Understand how stage colour mixes and which choices ruin faces.