Bypass the Crossfader, and Put It Back

Two actions this time, and they work as a pair. The first remembers how your crossfader is assigned and then takes it out of the signal path. The second puts back exactly what the first found. Between them, a transition runs with the deck faders owning the audio outright.

Fifteen minutes. You need no licence for this — action authoring is not a licensed capability, and neither is anything the pair uses.

Before you start

Author Your First Action done. You'll use the same Step Editor, and this tutorial assumes you know your way around it.
Traktor running with the Fusor mapping loaded. The crossfader-assign controls are Traktor's today; other apps are being added alongside their setup guides.

Why a pair

Crossfader Bypass decouples the crossfader from the audio, so deck levels come from the deck-level faders alone. Plenty of DJs mix that way permanently; others want it only for the length of a transition. Flipping it by hand mid-set means diving into a menu, which is why an action is the better answer — see Crossfader Setup and Deck-Level Modulation for what each setup does to your audio.

But "turn it off" is only half a feature. Turning it back on is the other half, and it is the half that goes wrong, because there is no single right answer to put back — your assignment is yours.

So the pair is built around remembering rather than assuming:

	What it does
Pre-run half	Reads your four decks' crossfader assignments and stores them under a name, then switches all of them off.
Post-run half	Writes back whatever was stored under that name.

There is a one-way version of this in your library already, xFader pass thru. It switches the assignments off and stops there — useful on its own, and you'll see why it isn't the pre-run half of a pair by the end of step 4.

1. Create the pre-run action

Library menu → Actions in the window header → Actions sub-tab.
Blue + in the list header.
Name it Crossfader Bypass On.

On the Notes tab, set Description to Remembers the crossfader assignments, then bypasses the crossfader. Click out of the field to commit.

Set Apps to traktor. Unlike the bass kill in the last tutorial, this one is not universal — it drives Traktor's crossfader-assign controls.

Open the Code tab, then the pencil icon at the right end of the tab bar to open the Step Editor. Set the Short ID to XfadeByp.

2. Remember what's there

Click Add step, then open the card's type selector and choose CAPTURE.

A CAPTURE card has two fields, and neither is a value:

Name — type xfader_assigns. This is the label the snapshot is filed under, and the post-run action will ask for it by exactly this name. Spell it somewhere you can copy from.
Addresses — this is the multi-select variant of the address picker you used last time. Picked addresses appear as chips above the trigger, and anything already picked drops out of the list so you can't add it twice.

Open Addresses and expand the Common region. Crossfader assignment lives there rather than under Deck A–D, because assigning a deck to a side of the crossfader is a mixer decision, not a deck one. Pick all eight:

Deck A — Xfader Assign Left      Deck A — Xfader Assign Right
Deck B — Xfader Assign Left      Deck B — Xfader Assign Right
Deck C — Xfader Assign Left      Deck C — Xfader Assign Right
Deck D — Xfader Assign Left      Deck D — Xfader Assign Right

Typing assign in the search box narrows to exactly these.

All four decks, not just the two you're mixing on. Bypass is a mixer-wide state; leaving C and D assigned means a deck you weren't thinking about is still being attenuated by a crossfader you believe is out of circuit.

3. Switch them off

Eight SET steps, one per address. For each: Add step, Address → Common → the assignment, Value → OFF.

The Value dropdown offers ON (1) and OFF (0) here, because these are switches rather than knobs — the value field takes its shape from the address, the same way it offered you CUT and UNITY for an EQ band.

Nine cards now, and they run top to bottom: the CAPTURE first, then the eight SETs. That order is the whole point. Capture reads the current values; if a SET ran first you would snapshot the state you just imposed, and the post-run action would restore the bypass instead of undoing it.

Click Save in the footer. The unsaved marker in the header clears.

4. Create the post-run action

Back in the Library list, blue + again. Name it Crossfader Bypass Off, description Restores the crossfader assignments remembered by Crossfader Bypass On., Apps → traktor. Open the Step Editor and set the Short ID to XfadeRst.

One step. Add step → type selector → RESTORE.

The card has a single Name field, and it's a plain text box. Type xfader_assigns — the same name, character for character.

Why a text box and not a dropdown. When an action contains its own CAPTURE steps, the RESTORE field becomes a dropdown of their names. This action has none, so there is nothing to offer you and it falls back to free text. That is the tell that you're building half of a pair.

Click Save.

The thing that makes this work

A snapshot is not stored inside the action that took it. It lives on the engine, under its name, for as long as Fusor Studio is running. That is why one action can remember and a completely different one can put it back, with a whole transition in between.

It also means the name is global. Capture xfader_assigns again anywhere and you overwrite what was there, so name snapshots after what they hold rather than after when you took them.

Now compare this to the xFader pass thru action already in your library. That one switches all eight assignments off, and there is no partner that restores them — the version that used to accompany it wrote back a fixed layout (A and C on the left, B and D on the right) rather than what it found. For a DJ using that layout it looks identical. For anyone else it quietly replaces their setup with someone else's. Remembering costs one extra step and can't be wrong.

5. Try the pair by hand

You can fire both from pads before wiring them into anything, which is the fastest way to see the behaviour.

Library header → Actions → Packs sub-tab.
Right-click the Tutorial pack → Edit Pad Slots.
Drag Crossfader Bypass On onto slot 3 and Crossfader Bypass Off onto slot 4.
Back arrow, then turn on Pad Mode with the grid icon in the menubar.

In Traktor, set your crossfader assignments to something you'll recognise — assign Deck A left, Deck B right, and leave C and D unassigned.

Click pad 3. All four decks go unassigned; the crossfader is now doing nothing to your audio.

Click pad 4. Deck A is back on the left, Deck B on the right, C and D still unassigned. Not a default layout — yours.

Now the case that shows why the pair is safe to attach to anything: switch every deck off by hand, then press pad 3 and pad 4 again. Capture reads off, the sets write off, restore writes off. For a DJ who already lives in bypass, the pair does nothing at all, and it needed no setting to tell it so.

What you learned

That CAPTURE names a snapshot and takes a list of addresses, through a multi-select picker.
That snapshots live on the engine, not inside an action, so a pre-run and a post-run action can share one.
That step order inside CAPTURE-then-SET is load-bearing.
That crossfader assignment is a mixer control, which is why it's under Common.
That restoring what you found beats writing back an assumed layout.

Where to next

Build a Constant-Power Crossfade — the last tutorial, and the one that puts this pair to work inside a real fusor.
Crossfader Setup and Deck-Level Modulation — the three setups, and what each does to a running fusor.
Action File Reference → CAPTURE — snapshot scope, naming, and what happens when a restore finds nothing.