Arming and Running a Transition

Once you've loaded a fusor, the next step is to arm the player. Arming tells Fusor Studio "I'm ready, start the transition when the trigger condition is met." What counts as "the trigger" depends on which mode you're in.

This chapter walks through the full lifecycle of a transition: arming, starting, running, and completing.

Before you arm

A few things need to be in place before the Arm button does anything:

• A fusor must be loaded. Without one, the Arm button is inactive. See Loading a fusor.
• For Auto Run Mode, the bars and BPM values need to be sensible — they define the timing window. In Manual Run Mode the bars/BPM readout is hidden, because the crossfader drives the timing.
• Tempo Ramp can be on or off. If on, arming triggers an additional sync sequence before the transition starts.
• In Auto Run Mode, Start-with-Incoming can be on or off. See "What arming does" below for what changes when it's on.

What arming does

Arming tells Fusor Studio you're ready for the transition to start. While armed, the player waits for the start trigger. What that trigger is depends on the mode, and in Auto Run Mode, on whether Start-with-Incoming is on.

Fusor Studio never runs a control-state capture while you're armed or while a transition is running: capturing can reset deck roles and rewrite control positions, either of which would disrupt an armed player or a run already under way. If a capture comes due during either (telemetry recovering while you're armed and waiting, for example), it's held until you return to Idle, and the status line marks the wait with a RECAPTURE PENDING — prefix in grey. See The Player Window for the full prefix rules. The wait doesn't block arming or starting.

Manual Run Mode

Click the Arm button (the large left-hand button on the progress strip). The button lights up to indicate you're armed.

While armed, the player is waiting for crossfader movement. As soon as you move the crossfader in the direction of the incoming deck, the transition starts and progress follows the crossfader.

The status line reads "Armed: move crossfader to start."

Auto Run Mode (default: press Play)

The Arm/Play/Pause button shows the PLAY label. Pressing it both arms the player and starts the transition.

This is the default Auto Run Mode flow. Fusor Studio doesn't wait on the incoming deck's state. The transition starts the moment you press Play. While loaded but unarmed, the status line reads "Unarmed"; once armed it reads "Armed: Press Play to start".

Auto Run Mode with Start-with-Incoming on

Turning the Start-with-Incoming toggle on arms the player in a different waiting state: instead of a Play button, the arm control becomes a solid dot, and the trigger is now the incoming deck starting to play. Fusor Studio watches for telemetry saying the deck holding the incoming role has begun playback, then starts the transition timer.

The status line reads "Armed: starts with incoming deck" while it waits.

Where the toggle is and when it can't be clicked are in Transport Controls; which path to choose, and what else changes, is the deep dive.

In Blind Mode

Blind Mode leaves only the press-Play path. The other two triggers are both things Fusor Studio would have to see — crossfader movement, or a deck starting — and in Blind Mode it isn't listening. Arm shows PLAY and behaves exactly as it does while Online. See Blind Mode.

Disarming

You can disarm at any time before the transition starts. The gesture depends on which armed state you're in:

• Armed (Manual Run Mode). Click the Arm button.
• Armed (Auto Run Mode, default press-Play). There's no separate armed step; you just don't press PLAY. To clear a loaded transition without starting it, abort it, load something else, or change to another mode to disarm.
• Armed (Auto Run Mode, Start-with-Incoming on). Click the Arm dot or toggle Start-with-Incoming off.

Disarming returns the player to Idle with the same fusor still loaded.

Starting and the setup pause

The transition begins the moment your mode's trigger fires, whichever of the ones above applies to you.

The trigger only fires once the player is armed. Until then, crossfader motion and incoming-deck playback are just things happening in your DJ app; neither starts anything.

If the fusor has any setup work to do before automation starts, that runs first as a brief setup pause at the very start of the transition.

During the setup pause, progress sits at 0% while Fusor Studio runs any setup actions. For example, automatically assigning FX units to the incoming and outgoing decks, or running an authored pre-run action. Most fusors have no setup work, so the pause is invisible.

The status line names each setup action as it runs. On a quick setup — which is what setup should be — you'll see those flick past and nothing else. When something is genuinely making you wait, the line settles on Preparing, in both run modes, and where the app can predict how long the whole setup will take it says so: Preparing — starting in ~8000ms. It cannot always predict it, and in Manual Run Mode it deliberately declines to promise a figure it might not be able to keep, so a bare Preparing is equally normal. Either way, progress sitting at 0% during this stage is expected.

Setup has a hard ceiling of 5 seconds. If it runs longer than that, an error appears in the status line and the two modes part ways:

• In Auto Run Mode, the transition aborts back to the armed state.
• In Manual Run Mode, Fusor Studio skips whatever setup is left and runs the transition anyway. You keep the run; you lose the unfinished setup.

The same split applies to a single setup action that merely errors rather than overrunning the ceiling: Manual warns you and continues, Auto treats it as a failure. See Pre-run actions.

Once setup completes, the transition runs normally from that point.

Running

Once the transition is running, what you see and do depends on the mode.

In Manual Run Mode

The crossfader is the master clock. As you move it from the outgoing side to the incoming side, the progress meter advances; stop moving and progress stops. Move it back and progress reverses. You can go slow, fast, in fits and starts, even reverse course; the fusor follows.

In Demo: Manual Run Mode is unavailable, so this section does not apply — Demo runs every transition in Auto Run Mode. See Licensing.

The Play/Pause button on the progress strip becomes a Hold control while running — it renders as a single dot on the button (no "Hold" label appears on screen; that's just what this manual calls the gesture). Pressing it "freezes" the transition at its current progress, disconnecting the crossfader from progress until you press it again to resume. This is useful if you want to grab the crossfader for something else without disturbing the transition. The status line shows "Frozen" while held. When you resume, Fusor Studio caps how fast progress can re-attach to the crossfader to prevent abrupt jumps.

In Auto Run Mode

The total transition duration is computed from the transition's bars and BPM and becomes a fixed timing window. Progress advances on its own from 0% to 100%.

There are two distinct ways the transition can be paused, and they behave differently.

Pausing the fusor. Pressing the Play/Pause button on the progress strip. The fusor stops producing new values; parameter values freeze at their current position. The timing window keeps ticking the whole time. When you resume, Fusor Studio recalculates the pace from remaining-progress over remaining-time. The rest of the transition runs faster than originally planned to finish at the originally-scheduled moment. If you pause for long enough that the window runs out, there's no time left to finish; progress simply stops advancing where it is.

Pausing the transition. Stopping the incoming deck in your DJ app. The transition's clock stops too. When you resume the incoming deck, the transition picks up exactly where it left off, at its original pace. The transition's finish time is pushed back by however long the pause lasted. Stopping both decks does the same thing and says so on the status line (Both decks stopped); the incoming deck is still the one that resumes it.

Pressing Play/Pause stops the fusor's output; stopping the incoming deck stops the whole transition. They're different tools for different needs.

Fusor Studio never controls deck transport. The incoming deck plays or doesn't based on what your DJ app is doing. Fusor Studio just reads that state to decide what the transition should do.

The status line shows the current mode label while running.

Manual takeover (Auto Run Mode, Online only)

While a transition is running in Auto Run Mode with full telemetry (Online), the user can perform manual takeover by moving DJ-app controls that Fusor Studio is automating. Two forms:

• Per-control takeover. Moving one automated control in your DJ app (an EQ knob, a filter, and so on) stops Fusor Studio from automating that one control for the rest of the transition. Takeover is permanent for the duration; the control stays manual even if you let go.
• Whole-transition takeover. Moving the crossfader during an Auto Run Mode running transition converts the entire transition to manual operation from that point on. The crossfader becomes the master clock.

Both forms require full telemetry. In Blind Mode, Fusor Studio has no way to detect that the user is moving controls, so manual takeover is unavailable.

Aborting

Aborting terminates a transition immediately and permanently. There's no resume; you'd load the fusor fresh and start over. It's available while a transition is under way — running, paused, or in its setup pause — and deliberately hard to fire by accident. Transport Controls has the gesture and the availability rules.

Abort does not run the completion sequence. Roles don't swap, nothing is put back, and no post-run actions fire — the fusor stays loaded and the player returns to Idle. Your mixer is left exactly as the transition left it: EQs part-swept, faders mid-travel, FX still engaged. That's deliberate. Abort is what you press when the mix has gone wrong, and the last thing you want in that moment is the app moving controls you're already reaching for.

What abort does do is re-derive which deck is outgoing and which is incoming from where the crossfader ended up. Abort a transition late, with the crossfader over on the incoming side, and the roles can come out flipped — check the direction indicator before re-arming, and use Manual Role Swap if it's wrong.

For where Abort sits against the resumable options, see Hold vs Pause vs Abort.

Putting things back: the RESTORE button

Leaving everything as-is is right in the moment, but it leaves you with a mixer to tidy by hand — and some of it you can't easily tidy, because a fusor's setup actions can change things you didn't touch and might not notice, like which crossfader side a deck is assigned to.

So after an abort, the Abort button becomes RESTORE. Hold it the same way you held Abort, and everything goes back to where it was before the run started: the controls Fusor Studio was driving, any FX routing it set up, and anything the fusor's own post-run actions put back. It's the same button and, on a hardware controller, the same command — you press the one button twice.

It waits a second first. Hitting Abort twice in a panic is a reflex, so for one full second after an abort the button still reads Abort and still behaves as Abort. Only after that does it offer RESTORE. Nothing is lost if you do press twice fast; the second press is simply refused.

On a started run, RESTORE is audible. "Before the run" means the outgoing deck full and the incoming deck not yet in. Press it half-way through a mix with both decks playing and it snaps the sound back to before the mix started, in front of the audience. That is exactly what an "undo this transition" gesture should do, and it is a decision you should make on purpose. If you only want part of it back, don't press it — move those controls by hand instead. RESTORE is all or nothing.

Before a run has started it's silent, and Fusor Studio does it for you. If the transition never got past its setup pause — you aborted during setup, both decks stopped, or a setup action failed — nothing was mixed and nothing is audible, so there's nothing to decide. Fusor Studio undoes the setup by itself and says Pre-run setup unwound on the status line. There's no button to press.

The offer doesn't expire on a clock. It stands until you arm the next transition, load a different fusor, or press it. Once you press it, it's used up and the button goes back to reading Abort. And if there's genuinely nothing to put back — you armed, changed your mind, and aborted without ever starting — no RESTORE appears at all.

RESTORE does not un-abort the transition. It puts controls back; it does not resume the mix, and it does not move the deck roles.

In Blind Mode there's no RESTORE button. Fusor Studio never saw where your controls were, so it has nothing to put them back to.

Completion and role swap

When the progress meter reaches 100%, the transition enters its Completing phase. In every mode with telemetry — Manual as much as Auto — completion is gated on the outgoing deck stopping, and the arm control becomes an End button you can press to commit instead of waiting.

End ends the transition, not the track. Pressing it doesn't stop the outgoing deck; it tells Fusor Studio to stop treating that deck as the outgoing side of an active transition. The track keeps playing in your DJ app until you stop it or let it ride out.

In Auto Run Mode

1. Progress reaches 100%. The Arm/Play/Pause button changes to an End button (rendered as END on the button face).
2. Fusor Studio waits for telemetry confirming the outgoing deck has stopped playing. If it does, completion proceeds automatically. If it doesn't (for example, the crossfader is bypassed or the outgoing volume isn't at zero), the player waits. The status line shows Completed — stop outgoing deck or press End. The user can press End at any time to commit.
3. The deck roles swap. The deck that was incoming becomes the new outgoing deck; the deck that was outgoing is now positioned to be the next incoming deck.
4. If the Snapshot / Restore setting is on (Settings → Guards, and on by default), the outgoing deck's DJ-app controls are restored to the state they were in when the transition started.
5. Any post-run actions the fusor carries are run, with the same 5-second ceiling the setup queue has. See Pre-run actions.
6. The Tempo Ramp toggle resets to off, unless Persist tempo ramp across transitions is on in Settings → General, in which case it stays armed for the next run.
7. The player returns to its loaded-but-idle state, ready for the next transition.

In Manual Run Mode

The flow is similar, with one important difference: while the transition is at 100% waiting for the outgoing deck to stop, the user can still walk the crossfader back, which returns the transition to the Running state and lets you continue adjusting from there. This is the Manual Run Mode equivalent of "I'm not committed yet, let me back this out."

If the user doesn't back out, the same End path applies: outgoing deck stops naturally → completion proceeds, or user presses End to commit manually.

In Blind Mode

There's no telemetry to wait for, so completion is simpler: when progress reaches 100%, Fusor Studio fires the outgoing-stopped latch itself and the transition completes. Deck roles swap exactly as they do while Online. Snapshot restore is the one step that has nothing to do — with no telemetry there were no pre-transition values to capture, so controls stay where the transition left them. See Blind Mode.

Tempo Ramp

If Tempo Ramp is enabled, arming runs a tempo-sync setup sequence before the transition's automation begins. The status line reports what it finds, and the transition proceeds normally once tempo alignment is achieved. On apps that can't sync a stopped deck the sequence may be queued until the incoming deck starts.

During the run, the outgoing deck stays tempo master and Fusor Studio drives its tempo fader toward a target that lands both decks on the incoming track's natural tempo. The incoming deck follows via sync. See Traktor Pro Setup for the app-specific detail.

Tempo Ramp is for cases where the incoming and outgoing tracks have different tempos and you want them brought together without an audible jolt.

How transitions end

A transition can end in four ways. Three of them are covered above; the fourth is one Fusor Studio decides for itself.

Auto-abort is the one case Fusor Studio initiates, and it only applies before the run starts. If both decks stop while the transition is still in its setup pause, there is no run to hold on to, so Fusor Studio abandons it, disarms, and says Both decks stopped: aborted on the status line. Nothing had been mixed, so it also undoes the setup for you rather than offering you the choice.

Once the run has started, both decks stopping is not an ending at all. In Auto Run Mode it pauses the transition and waits, exactly as stopping the incoming deck alone does — the status line reads Both decks stopped: paused, the player stays armed, and starting the incoming deck again resumes the transition from where it stopped. The pause has no time limit. If you don't want to finish the transition, hold Abort; that ends it and offers RESTORE on the usual terms.

In Manual Run Mode a started run ignores it entirely. The crossfader drives the transition and your hand is still on it, so the decks stopping changes nothing: no pause, no status message, and the fader still moves the transition. This is the one place the two Run Modes read differently — in Auto, the deck telemetry is what paces the run; in Manual, you are.

Aborted and Disarmed leave the player looking the same afterwards (Idle, fusor still loaded), but they're different events: Abort interrupts automation that was already running, Disarm cancels a start that hadn't fired.

States at a glance

A quick summary of what the player can be doing at any moment:

The pickers are locked while you're in any state other than Idle. Loading a different fusor requires aborting or completing the current one.