Output
How rendered color leaves Spectralite as DMX over Art-Net or sACN, and how patch universes map to the universes on the wire.
Each frame, Spectralite decides what value every fixture channel should hold. The output stage takes the color that the engine solved for every fixture. It packs the channels of each fixture into DMX and sends the result onto your network. For the field-by-field walkthrough of the dialog, see the Outputs dialog reference.
A fixture is one controllable light with a block of DMX channels. If that term is new, read Fixtures first. The value each channel carries comes from the engine's color solve. Output addresses those values and wraps them in packets without changing them.
Two ways to carry DMX over Ethernet
Spectralite sends DMX over the network using one of two standard protocols. Spectralite has no USB or serial DMX output, so every path to your rig runs over Ethernet.
- Art-Net carries DMX in UDP packets on port 6454.
- sACN (the ANSI E1.31 standard, sometimes written Streaming ACN) carries DMX in UDP packets on port 5568, delivered by multicast.
Both carry the same 512 channels per universe. They differ only in how they are addressed and delivered on the network. Pick the one your receiving hardware speaks. You can run more than one output at once. For example, you can drive a rig over both protocols in parallel, or feed the same show to a primary and a backup path. To switch a rig between Art-Net and sACN, enable or disable its outputs.
For the fundamentals of DMX itself, such as what a channel is and how addresses stack, see Understanding DMX.
The universe model
A universe is a group of 512 DMX channels. Each fixture occupies a run of channels inside a universe, from its patch address onward. A rig larger than 512 channels spreads across several universes. For output, two things matter: the universe that each fixture's channels land in, and the number that universe carries on the network.
Spectralite's patch sheet numbers universes starting at 1. The two protocols count differently. Art-Net's first universe is 0, and sACN's first universe is 1. A new output already carries the right setting for its protocol, so your patch universe 1 arrives where a standard receiver expects it.
A new output applies this mapping:
| Patch universe (what you see) | Art-Net universe on the wire | sACN universe on the wire |
|---|---|---|
| 1 | 0 | 1 |
| 2 | 1 | 2 |
| 3 | 2 | 3 |
The Art-Net column is one lower because Art-Net counts from zero. Each patch universe still maps to exactly one Art-Net universe, and the mapping needs no adjustment. sACN starts at 1 and reserves universe 0, so its column matches the patch sheet. For the same reason, a new sACN output has a different preset from a new Art-Net output.
Universe Offset is for third-party alignment only
Each output has a Universe Offset field. It shifts every universe that output sends up or down by a fixed amount. A new output already has the value that produces the default mapping, so most shows never touch the field.
Change the offset only when a receiver on the other end numbers its universes differently from Spectralite's default. For example, a lighting node can expect the data you patched as universe 1 to arrive as Art-Net universe 5. In that case, raise the offset so the whole output shifts to match. The offset changes the mapping and leaves your patch alone.
Do not set an offset to convert between 1-based and 0-based numbering. Spectralite already does that conversion for each protocol. An offset on top of that conversion shifts every universe by an extra step, and your data goes to the wrong place. Unless a specific receiver forces a different number, leave the offset at its default.
When you edit the field, the dialog shows a live preview of where each universe will land. It also flags a mapping that the protocol cannot carry. For example, sACN has no universe 0, so an offset that pushes a universe down to 0 is invalid. In that case, the editor tells you the value to use instead.
Broadcast, multicast, and unicast at a glance
How an output reaches the network changes what traffic your switches carry and which devices receive it. The default gets a rig running, and the alternatives matter on larger or busier networks.
| Mode | Who receives it | When to use it |
|---|---|---|
| Unicast (Art-Net default) | Only the specific fixtures that need each universe | Busy or shared networks where flooding every device is wasteful |
| Broadcast (Art-Net) | Every device on the subnet, in one burst per frame | Small, dedicated lighting networks. No per-fixture addressing needed |
| Multicast (sACN, always) | Only devices that subscribed to each universe's group | sACN's normal delivery. Receivers join the universes they use |
In Art-Net Unicast, each fixture holds the destination address. You set a target IP per fixture, and Spectralite sends each universe only to the fixtures that asked for it. A fixture with no target set receives nothing in unicast mode. In sACN, delivery is always multicast to a group derived from the universe number, so receivers subscribe to only the universes they use.
Because sACN uses multicast, a managed switch usually needs an IGMP querier for sACN packets to reach their destinations. On the sending machine, allow outbound UDP on port 6454 for Art-Net and 5568 for sACN through any firewall. Art-Net setup covers network and receiver setup step by step.
Where to go next
Outputs dialog
Every field on an output: protocol, network interface, offset, range, and mode.
Art-Net setup
Set up a network, choose broadcast or unicast, and get packets to real hardware.
Output and Networking
The full output and networking section, including troubleshooting.
Understanding DMX
Channels, universes, and addresses from the ground up.
Core Concepts
The whole signal flow, from fixtures to color to output.