This page explains what happens between arming a cue and firing it, and why that gap matters. Nothing here needs setting; it is background that explains a behaviour you will notice, and one you would otherwise mistake for a fault.
The problem it solves
Some sources need a moment before they can show anything. A web page has to load; a scene has to be built; a media file has to be opened and seek to its in point. If all of that happened at the moment you press GO, every one of those cues would start with a black dip of half a second or worse.
What the program does
The armed cue is prepared in advance. From the moment a cue turns green, the program opens what it needs, positions it at the in point and holds it there. When you press GO, the source is already standing by and the picture is there immediately.
That is the practical reason arming exists as a separate step, and the reason the list arms the next cue by itself after every GO: by the time you reach for the button, the next one has been ready for a while.
What you can see of it
Not much, and that is the point. What you may notice:
- A web page cue that was armed a few seconds ago comes up instantly, while one you arm and fire in the same second may still be assembling itself.
- The program’s log records for each GO whether the cue was already prepared. If someone is chasing a black flash, that line settles the question.
What is deliberately not prepared
A media cue is not played in preview. Video and audio only run when they are live — never while merely selected or armed. Arm a still or a scene and you see it in the preview straight away; arm a clip and the preview stays black until GO.
That is a choice rather than a limitation: an audio file that started playing because someone clicked a line would be on the monitoring output, and possibly on air, before anybody intended it.
A countdown in a scene stays frozen until the cue goes live, so the clock starts at the moment the audience sees it rather than at the moment you armed it.
Practical advice
Give the program the moment it wants. Arm the next cue as soon as the current one is running, rather than at the second you need it. On a list built the ordinary way — where the following cue arms itself — this happens without you thinking about it at all.