DMX addressing explained step by step (with no gaps in understanding)

A DMX address is the starting point for a fixture in the DMX data stream. The DMX controller continuously sends channel 1, channel 2, channel 3 and so on all the way up to channel 512 – all the time and in the same order, no matter what else happens in the system.

A fixture has no understanding of “functions”, “colours” or “gobos”. It only knows one thing: “I start listening from channel X and read the next N channels onwards.”

The address is therefore the first channel the fixture starts reading from. Everything after that depends solely on how many channels the fixture is set to use.

Start address + channel usage = the whole truth

Everything in DMX addressing can be reduced to one simple formula:

Start address + number of channels − 1 = last channel the fixture uses

This means that if you know the fixture’s start address and how many channels it occupies, you can always calculate exactly where it ends in the DMX universe.

Example:

The fixture uses 7 channels and has start address 25.

The calculation is:

25 + 7 − 1 = 31

That means the fixture uses channels 25 through 31.

Nothing more. Nothing less.

Why do conflicts occur?

Two fixtures must never use the same DMX channels unless they are intentionally meant to behave identically (so-called “mirroring”). Each fixture must have its own unique channel range in the DMX universe.

Typical mistake:

• Fixture A: address 1, 8 channels → uses channels 1–8

• Fixture B: address 5, 8 channels → uses channels 5–12

Here, there is overlap on channels 5–8.

The result is unpredictable behaviour, where movement and colours suddenly become “linked” between the fixtures. It can seem like a technical fault in the equipment, but in reality it’s caused by overlapping addresses. Without knowing and understanding the channel calculation, troubleshooting can become almost impossible.

This is by far the most common DMX mistake.

Before you set a DMX address, you should always know how many channels the fixture uses. The number of channels depends directly on the selected DMX mode.

Examples of modes could be:

• 3-channel mode (RGB)

• 6-channel mode (RGB + dimmer + strobe)

• 14-channel mode (moving head basic)

• 20+ channels (moving head extended)

The selected mode determines how many channels the fixture occupies in the DMX universe – and therefore how far its channel range extends.

The mode is typically selected:

• on the fixture’s display

• via DIP switches

• or via an internal menu

The address is meaningless without knowing the mode. Only when you know how many channels the fixture uses can you calculate a correct and safe start address.

Step 2 - Calculate the addresses correctly

Let’s take a realistic setup with four LED PAR fixtures, one moving head and one strobe.

Channel usage is as follows:

• LED PAR: 6 channels per fixture

• Moving head: 14 channels

• Strobe: 2 channels

To avoid overlap, the addresses are calculated consecutively:

Fixture 1 (LED PAR)

Start address 1 → uses channels 1–6

Fixture 2 (LED PAR)

Start address 7 → uses channels 7–12

Fixture 3 (LED PAR)

Start address 13 → uses channels 13–18

Fixture 4 (LED PAR)

Start address 19 → uses channels 19–24

Moving head

Start address 25 → uses channels 25–38

Strobe

Start address 39 → uses channels 39–40

All devices are then neatly placed in the DMX universe without overlap. The system is logically structured, easy to understand and easy to troubleshoot.

Step 3 - Set the address physically on the fixture

There are three common methods for setting DMX addresses, and each has its advantages and challenges.

A) Numeric display

This is the most user-friendly method. You go into the fixture’s menu, select “DMX address”, enter the start address (for example 25) and confirm.

The advantage is that no calculation is required, and troubleshooting is quick and straightforward. The downside is that the fixture must have power before you can see or change the address.

B) DIP switches (binary addressing)

This is the most misunderstood method. Each switch represents a fixed value:

1 – 2 – 4 – 8 – 16 – 32 – 64 – 128 – 256

To create an address, you add the values together.

Example:

Address 37 =

32 + 4 + 1

This means switches 1, 3 and 6 are turned on (because they represent the values 1, 4 and 32).

Typical mistakes are counting the switch number instead of the switch’s value, or forgetting to reset previous settings. DIP switches require discipline and an understanding of binary structure.

C) Software / RDM

Modern systems can address fixtures via RDM (Remote Device Management). Here, you can set addresses directly from the controller, get an automatic channel overview and quickly reconfigure your setup.

The advantage is efficiency and oversight. The downside is that not all fixtures support RDM, and it requires a compatible setup.