Mixing

Mixing is making every track sit at the right level, in the right place, with the right sound. Every track, bus and the Stereo Out has a channel strip. You see the chosen track's strip on the left of the arrangement, and every strip side by side in the mixer (⇧⌘M).

The channel strip

From the top of a strip to the bottom:

  • Input: where an audio track records from.
  • Inserts: plug-ins that change the sound, from top to bottom. Click an empty slot to add one; drag one to move it.
  • Sends: copies of the sound going to a bus.
  • Pan: left or right.
  • Fader: how loud. Double-click it for 0 dB. The scroll wheel over a fader or a pan turns it too.
  • M mutes, S solos (only soloed channels are heard), R arms for recording, I monitors the input. The Stereo Out has only M: everything plays through it, so there is nothing for it to solo.

The mixer's views

Open the mixer with ⇧⌘M. The bar along its top chooses what it shows:

  • Single: the selected track and the path its sound takes: the buses it sends to or plays through, and the output. Good for following one signal from source to speaker.
  • Tracks: every track, the buses tracks actually reach, and the output.
  • All: every channel, including a bus nothing feeds.

The filter buttons beside them, Audio, Inst, Aux, VCA and Output, show only those kinds of channel. Turn on several to see several kinds; with none on, all are shown.

The mixer's View menu has Wide Channel Strips, Show Row Names and Show Load. The close button (an x) at the far right closes the mixer; when the mixer is in a window of its own, close the window instead.

Undo while mixing

Every fader, pan or send move is one undo step, on one channel or on several selected, whether by mouse, scroll wheel, VoiceOver or a controller; clicking a control without moving it is none; while automation writes, the whole pass is one step.

Undo names the step, for example "Volume Change", or "Volume Change (3 Channels)" when selected channels moved together. A turn of the scroll wheel counts as one move once the wheel is still.

Selected channels move together

To move several channels at once, select their tracks, then move the fader, pan or send of one of them. The others move by as much: faders and sends by the same number of decibels, so their balance stays. A send carries the other selected tracks' sends to the same bus. To move just the one channel, hold Option as you take hold of it.

Tracks in a group follow the group's own rule instead (see Groups).

Channel basics

Small tools every engineer reaches for:

  • Polarity (the Ø button) flips the wave upside down. Use it when two microphones on one sound cancel each other.
  • Trim turns the sound up or down before the plug-ins.
  • Delay moves a track a few milliseconds earlier or later.
  • Width makes a stereo sound narrower (down to mono) or wider.
  • Pan mode: Balance turns one side down; Stereo Pan moves both sides together.
  • On the Stereo Out, Mono folds the whole mix to mono to check it, and Pan Law sets how loud a centred sound is against one panned hard.

Sends

A send copies a track's sound to a bus, for a reverb or a delay that many tracks share.

  • Click an empty send slot and choose a bus, or Send to New Aux to make one.
  • Each send has its own level and its own pan.
  • Post Fader (the usual one) follows the track's fader. Pre Fader does not: use it for a headphone mix.

Sends on Faders

Sends on Faders is the quick way to balance a reverb or delay bus. Click Sends on Faders in the mixer's bar and choose a bus. Every track's fader then shows and sets that track's send to the bus instead of its volume; a track with no send to that bus has no fader to move. The menu's label shows the bus while it is on.

Choose Off in the same menu to put the faders back to volume. If the bus is deleted, the faders go back by themselves.

Buses

A bus is a channel that plays whatever is sent or routed to it. Put a reverb on a bus and send several tracks to it. A bus can play into another bus. Nebula refuses a route that would feed a bus back into itself.

Groups

A group links tracks so they move together. Choose a group in a strip's group slot, then choose what it links: Volume, Pan, Mute, Solo, and Editing (Selection) for editing them as one (see Recording several tracks).

Track stacks

A track stack gathers tracks under one track of their own. Choose the tracks, then Track ▸ Create Track Stack… (⇧⌘D) and pick a kind:

  • Summing Stack: the tracks play into a bus of their own, the stack's track. Add plug-ins, sends and automation to all of them at once, as a submix.
  • Folder Stack: only gathers them: one fader, mute and solo for all, their sound unchanged, no effects.

The arrow on the stack's header shows or hides its tracks; hidden, the stack's row shows an overview of every region inside it. The header says SUM or FOLDER and how many tracks it holds, with its own M and S. A summing stack also has an automation button that shows its bus volume, pan and mute lanes.

Right-click the stack's header to rename it, convert it to the other kind, Flatten Stack (its tracks go back where they were) or Delete Stack and Its Tracks. Stacks can sit inside stacks.

Solo-safe

Option-click a strip's S to make it solo-safe: it is never silenced by another channel's solo. A reverb bus is a good one to keep safe. A soloed bus always brings the tracks that feed it.

Plug-ins

Click an insert slot to choose a plug-in. Your favourites come first. The inspector's Effects tab shows the selected track's inserts as its channel strip does: click one to open it, point at it for its power button, and use its menu to replace, move up or down, wrap in a rack or remove it; ＋ AUDIO FX and ＋ MIDI FX add one. The Plug-in Manager (Nebula DAW ▸ Plug-in Manager…) lists every plug-in on the Mac and says why one did not load.

To bypass an insert, point at its slot and click the power button (Bypass), or use the bypass button in the plug-in's window. Bypass is click-free, even while the song plays: the sound crossfades between the plug-in and the dry signal over 20 ms. The track keeps its timing, because the delay compensation for the plug-in's latency stays as it was.

Nebula's own effects include Chorus, Phaser, Tremolo (a tremolo and an auto-pan), Auto-Filter and Saturation; the chapter "The Tuner, the Analyzer and Nebula's effects" describes them.

Racks

A rack holds two to eight chains of plug-ins side by side in one insert slot, and sums what they make back into the channel: a parallel compressor, a multiband chain, effects on only the sides. Choose FX Rack from an insert slot's menu, then click the rack's slot to open its window.

  • Split says what each chain hears. Parallel: all of the signal, so the chains add (two empty chains are 6 dB louder). Frequency: a band each, between Crossovers you type in hertz; the bands are Linkwitz–Riley, so with nothing in them they add back to the sound as it was. Left / Right and Mid / Side split two chains into the two sides, or the middle and the sides, and also add back to the sound as it was.
  • Add Chain adds a chain at the right, up to eight; the × over a chain removes it. A rack keeps two.
  • Each chain has a name, M (mute), S (solo: only soloed chains are heard), a level from −60 dB (off) to +12 dB, and a pan. A drag is one undo step.
  • ＋ Audio FX in a chain adds a plug-in at its end. Click a plug-in's name to open it; the power button bypasses it, the arrows move it, the minus removes it.
  • A chain with slower plug-ins than its neighbours is not late: the faster chains are held back to meet it, and the rest of the mix waits for the rack as it waits for any plug-in. Bypassing the rack keeps that timing.
  • The eight macros over the chains each turn plug-in parameters inside the rack, each over its own range. Right-click a macro to map a parameter, edit its ranges or name it, or learn a controller for it. A macro can be automated: its lane plays into what it turns.
  • To put a plug-in that is already on the channel into a rack, choose Wrap in FX Rack in its slot's menu (the arrows on the slot). It becomes the first chain's first plug-in, beside an empty chain: a parallel compressor in one step.

Rack presets

A rack takes a while to build, so keep it. In the rack's window, open Rack Presets and choose Save Rack…, or choose Save Rack… in the rack slot's menu. The rack is saved in the Library's Racks, with every plug-in inside it as it sounds now, each chain's level, pan, mute and solo, an instrument rack's layers and zones, and the macros with what each turns.

  • To load one, choose it under Rack Presets in a rack's window: it replaces that rack's chains in one undo step, and the window stays open. Load Rack… in a slot's menu puts a saved rack in place of that slot, from any folder.
  • An instrument rack goes in an instrument track's instrument slot: choose Load Instrument Rack… in that slot's menu.
  • In the Library, click Racks, then double-click a rack to put it on the selected track: an FX rack after its inserts, an instrument rack in place of its instrument.
  • A rack loaded twice is two racks: each has plug-ins and macros of its own.

Claude can do this for you: ask it for a parallel compressor on the drums, to split the bass at 120 Hz and saturate only the top, or to widen only the sides of the pad. It can save a rack you like to the Library and load it in another song (save_rack, load_rack).

Mix scenes

A mix scene keeps the mix under a name, so a verse balance and a chorus balance, or a rough mix and the client's mix, are one click apart. Scenes are saved with the song.

  • To save one, choose Scenes ▸ Save Mix Scene… in the mixer and name it. It holds every channel's volume, pan, mute, solo, sends and plug-in bypass. Save Mix Scene with Plug-in Settings… keeps every plug-in's settings as well.
  • To recall one, choose its name under Recall in the Scenes menu. A recall is one undo step.
  • Each scene has its own menu in Scenes: Recall, Update with the Mix Now, Rename… and Delete.
  • To recall only part of a scene, untick kinds of setting under Recall Sets (Volume, Pan, Mute, Solo, Sends, Plug-in Bypass, Plug-in Settings). Under On, choose Every Channel or Only the Selected Tracks. The scene remembers these choices.

Claude can do this for you: ask it to save a mix scene called "Verse", list the scenes, or recall one.

Meters

The mixer's View menu ▸ Meters sets how every meter reads:

  • Position: Pre-Fader, Post-Fader or Post-Pan, where the meter listens.
  • Show: Peak, RMS or Peak + RMS.
  • Scale: dBFS, or K-12, K-14 and K-20 for mixing to a K-System level.
  • Peak Hold: 2 Seconds, 5 Seconds or Until Cleared.
  • Clear All Peaks and Clear All Clip Indicators.

The peak readout on each strip shows the highest level the channel has reached. Click it to clear it; Option-click to clear every channel's.

The clip light turns on when a channel goes over and stays on until you clear it, so you know it clipped even if you were not looking. Click it to clear it; Option-click to clear every channel's. View ▸ Clear All Clip Indicators clears them all.

The Stereo Out shows its loudness in LUFS while the song plays: I is the integrated loudness of everything since the measurement began, S the short-term loudness of the last few seconds. Click it to start measuring again, for example before playing the chorus.

Surround

A song can be stereo or surround: LCR, Quad, 5.0, 5.1, 7.0, 7.1, 5.1.4 or 7.1.4. Every channel is a speaker, in the order L R C LFE, then the surrounds, then the heights.

  • To make the song surround, click the STEREO box under the Stereo Out's pan and choose a format, or choose File ▸ Surround Format. Choose Stereo to go back. Each choice is one undo step, and each format can have a key: give it one in the Key Commands window.
  • On a surround song every track and bus has a surround panner where its pan knob was. Drag the dot: where it points is where the sound comes from, and how far it is from the middle is how focused it is — in the middle it comes from every speaker. A stereo track starts at the front, on the left and right speakers, so it sounds as it did in stereo until you move it.
  • Click the panner for the whole panner: Direction, Spread (how far apart a stereo track's two sides are), Height (into the ceiling speakers of 5.1.4 and 7.1.4), LFE (how much goes to the subwoofer channel) and Diversity. Front puts it back. A drag is one undo step.
  • A bus has its own format: choose it in the small box beside its width (ST). A 5.1 reverb return keeps its six channels through its plug-ins and fader. A track's send into it is placed where the track is placed. A surround bus playing into a smaller one is folded down to fit.
  • A plug-in on a surround channel works on the front left and right; the other channels pass it, kept in time with its delay.
  • The meters of the Stereo Out and of a surround bus show a bar for every channel, in the format's order.
  • DMX plays the mix folded to stereo on outputs 1 and 2, to check how it sounds on two speakers, as MONO checks it on one. It never changes a bounce. It lights by itself when the audio interface has fewer outputs than the format needs: then you hear the fold until you plug in one with enough.
  • Surround Outputs… in the format menu chooses the interface output each channel plays on. Left and right are always outputs 1 and 2; the rest follow in order, the centre on output 3, unless you choose otherwise. In Order puts them back.

A surround bounce writes every channel: see Bounce and export.

Claude can do this for you: ask it to make the song 5.1, to put the strings behind you, to make the reverb bus 5.1 or to put the centre on output 7.

Control Room and talkback

The Control Room is what you hear, apart from the song. The Stereo Out still makes the mix; the Control Room decides which speakers it plays on, how loud, and whether you are talking to the performers. It works when Nebula drives the audio interface directly (Audio Settings), and nothing of it is ever in a bounce, a stem or a take. It belongs to your room, not the song, so it is kept for this Mac: opening another song never moves your monitor level.

  1. Open the mixer and click CR in its bar, or choose Transport ▸ Control Room ▸ Control Room.
  2. Click the gear to set it up. Under Speakers, choose where each set is connected: A is the Stereo Out's own outputs 1–2 unless you choose others, B starts on outputs 3–4. Choose one output for a mono speaker. Each set has a trim, so switching compares the speakers rather than their loudness. Add Speakers adds up to four.
  3. Under Talkback, choose the input your control-room microphone is on, and its level.

Then, in the bar:

  • A, B play on that set. The switch fades one set out and the next in. Next Speakers steps through them.
  • The slider is the monitor level. The Stereo Out's fader and every bounce are not touched by it.
  • DIM turns the speakers down by the dim level, 20 dB unless you set another in the gear.
  • MONO folds the speakers to mono.
  • TALK puts your microphone into every cue mix — each bus sent to a hardware output past 1–2 — and dims the speakers while it is on, so the microphone does not hear them. Click it to latch it, or hold it to talk while held. It never reaches the speakers or the Stereo Out, and it is never recorded: a track recording from the talkback's input cannot be talked over, and arming one lets go of talkback.

Dim, Mono, Talkback and Next Speakers are also in Transport ▸ Control Room, and each can have a key in the Key Commands window. Every change glides over 10 ms, so nothing clicks. With the Control Room off the Stereo Out plays exactly as it always has.

Claude can do this for you: ask it to dim the speakers, to check the mix in mono or to switch to the B speakers. Talkback is yours alone: Claude never opens your microphone into the performers' headphones.

Controller assignments

Any knob, fader or button on a MIDI controller can move a control in Nebula.

  • Turn on MIDI ▸ Learn Controller Assignment (⌘L), click the control (a fader, a pan, a mute or solo, a send, a plug-in's knob, a Smart Control) and move the knob. Click the next control and move the next knob. Turn Learn off when you are done.
  • MIDI ▸ Controller Assignments… lists every assignment: its channel (or any), its mode, its range, Invert and its takeover. Learn one again, or delete it.
  • Mode: Absolute for knobs with ends and for faders; one of the three Relative modes for endless encoders (your controller's manual says which it sends); Toggle for buttons. A key or pad learned is a toggle.
  • Pickup (the default) moves nothing until the knob reaches the control, so nothing jumps. Jump takes the control at once.
  • One move is one undo step, and in Touch or Latch it is recorded as a lane, as a mouse drag is. Nothing is sent back to the controller.
  • Assignments are saved with the song.

Smart Controls

Each track has eight Smart Controls in the inspector: knobs that each turn one or more plug-in parameters, each over a range of its own. Nebula's own instruments and processors start with the eight a producer reaches for first. Right-click a knob to map a parameter, edit its ranges or name it; a range whose minimum is above its maximum turns that parameter the other way. A Smart Control can be automated (its lane plays into what it turns) and learned to a controller.