Manual

Getting started

Press play. Browsers keep audio muted until you interact with the page, so the first press is what switches the sound on — if you hear nothing at first, press it once more.

A new session opens with a few drum tracks already playing. Click any cell in a track's row of squares to add or remove a hit, and you are sequencing. From there:

• Change what a track sounds like with the dropdown next to its name.
• Click + add track at the bottom for another instrument.
• Use the numbered buttons at the top to move between 32 pattern slots.

Transport

The bar across the top controls playback for everything.

The second row is the keyboard-performance strip — scale, octave, chord and arp. It is covered under playing from your keyboard.

Patterns

Every session holds 32 pattern slots, numbered 1–32. Click a number to switch to it; the one you are editing is outlined. An empty slot is a blank canvas, so a slot per section (intro, verse, chorus) is a good way to build an arrangement.

Tracks

A track is one instrument plus its pattern. The header row holds its name, its engine (the instrument), and the length of its pattern.

The second row of buttons — roll, filter, env, fx, eq, comp, mod, aut — opens the panels described in filter, effects and dynamics and modulation and automation.

Wherever you meet a control you do not recognise, in a track row or in any of those panels, right-click it: you get what it does, and whatever movement is on it.

The step grid

The row of squares is the pattern. A filled square is a note; every fourth square is marked so you can find the beat.

• Click an empty square to add a note, or a filled one to remove it.
• Drag right from a note to make it longer.
• Drag up or down on a note to change its pitch.
• Double-click to set a note to full velocity.
• Right-click (or press and hold on a touchscreen) to open the step editor.

For drum tracks the pitch rarely matters, so the grid is all you need. For melodies, the piano roll is easier.

The piano roll

roll opens a pitch-by-time grid: pitches up the side, steps across. It is the best place to write a melody, and the only place to stack notes into a chord you draw by hand.

The lane underneath is velocity — drag a bar to make that step harder or softer. The buttons along the top shift every note up a step, double or halve the pattern length, or roll a new melody.

The step editor

Right-click any step to open everything that step can do beyond pitch and length.

Playing from your keyboard

On a desktop machine your computer keyboard always plays the active track — the one you clicked last, which is outlined. Typing in a text box is safe; note keys only play when no text field has focus.

The layout is a piano: the home row is the white keys and the row above holds the black keys.

• a s d f g h j k l — white keys
• w e t y u o — black keys
• z x — down and up an octave

Two ways to get what you play into a pattern:

• Record — switch on record, start playback, and notes land on the step passing underneath.
• Capture — play freely with the sequencer stopped or running, then press capture. Your last phrase is written into the track with its timing and note lengths, and the pattern is sized to fit.

Scale and chords

Tick scale and pick a root and a mode to lock your playing to a key. Everything you play on the white keys then belongs to that scale — the black keys go quiet, so there are no wrong notes. There are major and minor modes, pentatonics, blues, several exotic scales, and microtonal tunings.

The palette button next to it colours notes by pitch across the roll and grid, which makes repeated shapes easy to spot.

Chord mode

With chord on, each key plays a whole chord instead of one note. Pick the chord type and a voicing. With a scale active the choice collapses to on or off, because the chord is built from the scale itself — so each degree gets the quality it should have, and everything stays in key.

Chords you record or capture are stored as a chord, not as loose notes, so the roll shows a single labelled note you can retune or move in one go.

Arp

The arp box appears next to the chord picker. Switch it on and a held key arpeggiates as you play, at the rate, octave range and direction you choose. Chords you then record or capture carry those arp settings into the pattern.

Sound engines

The dropdown beside a track's name chooses its instrument. They are grouped:

The four sliders under the name — labelled per engine, for example harm, timb, morph and decay on a Plaits model — are that instrument's main tone controls. The labels change with the engine, so they always say what they actually do.

The 303

The 303 engine is modelled on the machine rather than approximated with a filter preset, so it responds to a pattern the way the original does. Its four sliders are the panel knobs: cutoff, reso, env mod and decay. Beside them sit the waveform switch, the accent depth and tuning.

Three things are worth knowing, because they are how you play it:

• Accent comes from step velocity. Push a step past about two-thirds and it accents: louder, brighter, and with the filter decay forced short. Turn the resonance up and consecutive accents stack into a rising squelch instead of each being separate — that pile-up is the sound of an acid line.
• Slide comes from note length. Draw a step longer than one cell and the note after it slides out of it: the pitch glides across and the envelope is not retriggered.
• Plain steps are clipped short, a little over half the step, which is what makes the part drive rather than run together. Lengthen a note if you want it to hold.

The filter loses low end as the resonance climbs, exactly as the real one does. That is why acid records run a 303 into a distortion pedal — reach for the track's fx panel and do the same.

The virus

Where the 303 is one idea done perfectly, the virus is a big polyphonic synth built for movement. Its four sliders are cutoff, reso, shape and decay; the four beside them are the levels of osc 1, osc 2, the sub and the noise. Everything else is in the three rows underneath.

Four things are worth reaching for first:

• Shape is one continuous morph from a sine, through a triangle and a saw, to a pulse — and at the very top the pulse width slider takes over. Sweep it and the tone changes character rather than just brightness.
• Unison is the hypersaw. Each note plays up to eight detuned copies of the whole oscillator section, spread across the stereo field. Two or three is a thickening; eight with the detune up is the wide trance sound.
• Two filters, not one. Each can be a low pass, high pass, band pass or notch, and you choose how they connect: in series (one into the other), in parallel, or split so filter 1 plays the left ear and filter 2 the right. A low pass into a high pass in series is a band pass you can sweep from both ends.
• Saturation sits between them, which is the whole trick — filter 2 tidies up whatever the saturator did to filter 1's output, so you can be filthy and controlled at once. It runs from a gentle warmth through hard clipping to a bit reducer and a rate reducer.

Sync is the other one to know: turn it on and osc 2 is forced to osc 1's pitch, so dragging the semi slider (or automating it) gives the classic tearing sync lead.

The dx7

Six sine waves. That is the entire instrument — no filter, no sub oscillator, nothing else. What you get out of it depends only on which sines are wired into which, and how hard. The panel is the same six rows whatever you are making: one row per operator, with its level, its frequency as a ratio of the note, and its own envelope.

Four things to know, in the order they matter:

• The algorithm is the wiring. There are 32 of them and you cannot make your own — that was true of the machine too. The dropdown draws each one: 1←2 means operator 2 modulates operator 1. Beside it the panel says which operators are carriers — the ones that reach your ears, whose level is simply volume. Every other operator is a modulator, and its level is how hard it bends the one below it. The carrier rows are highlighted, so you can always see which is which.
• Level is exponential, and level is everything. A modulator at half its slider is a sixteenth of full scale, so almost all of the interesting range is in the top quarter. Nudging one modulator level is how you program this thing.
• Every operator has its own envelope, which means the timbre has an envelope. A modulator that decays fast under a carrier that does not is a struck sound — that is the whole trick behind an FM electric piano, and it is why the dx7 made a noise nothing before it could.
• Feedback is the only thing in the machine making harmonics that is not another operator. Wind the fbk slider up and it stops being a tone and turns into noise — which is where the breaths and cymbals come from. Which operator carries it depends on the algorithm; the panel says which.

The four track sliders ride all six operators at once: bright is every modulator's level together (the fastest way to hear what a patch can do), fbk is the feedback, mod dec scales how fast the timbre falls away and decay how fast the note does.

Start from the voice dropdown rather than from silence — an electric piano, a bass, a bell, brass, a marimba, an organ and a pad. Load one and change a single operator level, and you are programming a dx7. Two others are worth knowing: vel makes playing harder raise the modulation index, so hard notes are brighter and not just louder, and key scale pulls the modulators back as you play up the keyboard — without it the top octave screams.

The guitar and the bass

Neither of these is a plucked-string preset. Each one models the whole chain a real one goes through — the string, the pickup that reads it, the amp it runs into and the speaker in front of the mic — because on these instruments the sound is the chain and not the note.

Both start from a tone dropdown of famous rigs. That is the honest way in: load the nearest one, then move a control and hear what that control is actually for. Loading a tone replaces everything, including the four track sliders, so nothing of the last one is left behind.

The guitar

The string is a waveguide with the losses of a real one: the highs die before the fundamental does, which is why a guitar note gets duller as it rings rather than merely quieter. Where you pick it notches harmonics out of it — bridge is thin and cutting, over the neck is round — and the pickup does the same again on the way out. Which pickup you choose is really a choice of where its resonance sits: a single coil peaks high and glassy, a humbucker low and fat.

The four track sliders are drive (how hard the amp is hit, on a log taper like the real pot), tone (the knob on the guitar itself, not the amp — roll it right down with a neck humbucker for the darkest sound the instrument has), bloom and sustain.

bloom is feedback, and it is worth knowing what it does. The speaker is coupled back into the strings, so past a certain point the energy coming back beats the string's own losses and the note stops decaying and starts growing. It needs volume — a clean amp barely blooms, a cranked one sings — and it stops when the note ends, exactly as taking your hand off the string does. Hold a long step on a high setting and listen to it climb.

The bass

Same string, wound and stiffer: its harmonics sit noticeably sharp of where the arithmetic says, and that disagreement between the pitch and the clank is most of what a bass sounds like. Flatwounds take it away along with the high end, which is why every record made before about 1970 sounds the way it does — that is the roundwound / flatwound select.

Two things on the panel are worth finding. fret is how hard the string is allowed to clatter against the fretboard; wound up with the hand control at the top, that clatter is what slap is. grind is distortion, but only above the xover frequency, with the clean low end put back underneath — distort a bass whole and the bottom disappears, which is why every bass overdrive worth having works this way.

The sliders are drive, tone, comp and sustain. Compression gets a slider of its own because a bass part sitting perfectly still under everything else is a compressor doing that, and it is as much the sound as the amp is.

Samples

Choose sampler as a track's engine and you are asked for a source: a file from your machine, or one of the bundled drum kits. The waveform button in the track header then opens the sample editor.

• Trim the start and end, and fade either edge.
• Slice a loop and play the slices from the grid, one per note.
• Fit a loop to the tempo, or leave it at its natural speed.
• Keep pitch locked so a tempo-fitted loop stays in tune, or unlock it to play the sample melodically.

Files you load stay in your browser. They are only sent anywhere if you save the session to an account or make a share link.

The wavetable editor

With the wavetable engine selected, the waveform button opens an editor where you draw the sound itself. A wavetable is a series of frames — single cycles of a waveform — and the wave slider sweeps between them.

• Draw straight onto the canvas, or build the shape with the harmonic sliders underneath.
• Load a starting point: basic shapes, or any of the bundled waveforms.
• Add frames and the wave slider morphs smoothly between them.
• Unison stacks up to 7 copies of the voice per note, spread apart by the track's detune slider, for a wide supersaw-style sound.
• Wave scan sweeps through the frames on its own — set the speed (free or in time with the tempo), the direction, and which part of the table it covers. Retrigger restarts the sweep on every note instead of letting it run continuously.

Filter, effects and dynamics

Each track has its own chain, opened from the buttons under its name.

The effects chain

Effects run in the order they appear in the panel, starting with amp: drive pushes the signal into everything that follows, so fuzz, the wave shaper, tape saturation and the crusher all bite harder, and out trims the level back afterwards. Both sit at unity in the middle.

After that come vinyl and cassette (wear, warble and noise), fuzz, ring modulation, a wave shaper, a bit crusher, auto-wah, chorus, phaser, flanger, pitch shift, delay and reverb. Each has a wet or amount control that does nothing at zero, so the panel is safe to explore.

glide lives here too: it slides the pitch between notes rather than jumping, for portamento leads and basses.

p-lock

A track normally has one sound and 32 patterns of notes. Move its filter and it moves everywhere, because the sound belongs to the track and only the notes belong to the pattern.

The p-lock button in a track's button row changes that for the pattern you are on. Locked, that pattern keeps its own sound; every pattern you leave unlocked goes on sharing the track's. So you can give the bass a bright, delayed sound for the chorus and leave the verse and the middle eight alone — and they still move together when you tweak them.

It is per pattern, so the button changes as you move around: it lights up on the patterns you have locked. In chain mode the sound changes come with the arrangement, on the bar.

Everything about the sound comes along:

• the engine's own controls — the four sliders and whatever panel it has
• the filter and its envelope
• the effects rack, the eq and the compressor
• the modulation assignments in the mod panel

What does not move is the instrument itself: the engine, and any sample loaded into it, stay put. A locked pattern is one instrument being played differently, not a different instrument.

Modulation and automation

Two ways to make a sound move. Both are per track, and both are worth using on almost anything that repeats for long.

mod — continuous

Assign an LFO to a parameter and it sweeps back and forth on its own. Pick the target, a shape, a depth, and either a speed in hertz or a division of the tempo so it stays in time. Filter cutoff is the classic target; effect amounts and the instrument's own tone controls work too.

aut — per step

Automation draws a value for each step of the pattern instead. Choose a parameter, and you get a lane under the grid where each step holds its own value — a filter that opens over 16 steps, a delay that only appears on the last beat. Automation lanes belong to the pattern, so each pattern can move differently.

Right-click any parameter

The two panels above list a whole track at once, which is the long way round when the question is what is moving this control. Right-click a slider, a switch or its label — anywhere: the instrument row, the filter, effects, eq and comp panels, the sample and wavetable editors — and you get a small window for that one parameter: what it does, whatever LFO or automation is on it, and a button to add either. It is also the quickest way to learn an unfamiliar control, since the explanation is the first thing in the window.

You do not have to go looking, either: a parameter with something on it wears a dot next to its label — green for an LFO, blue for an automation lane, grey for a lane you have switched off. Scan a track and you can see where its movement is coming from.

Saving, sharing and export

Without an account everything stays in your browser, which means clearing site data clears your work. An account is the way to keep it.

If something sounds wrong

• No sound at all. Press play once more — browsers hold audio back until you interact with the page. Then check that no other track is soloed, and that the track's volume is up.
• A track is silent. Look for a soloed track elsewhere, a muted one here, or a filter cutoff closed all the way down.
• Playback stutters. Reverb, granular and pitch shift are the expensive effects; a lot of them at once on a slow machine will do it. Closing other tabs helps more than you would expect.
• The playhead looks out of time with what you hear. Safari cannot report its audio delay, so the display is an estimate. Add ?vlat=0.2 to the address to tune it to your machine.
• An arp is not audible. The note is probably too short to fit more than one arp note. Lengthen it or choose a faster arp rate.
• Sound cut out after switching apps. Click anywhere on the page; the audio engine reconnects on your next interaction.

Credits and licences

seqbaby is built on other people's work. Thank you to everyone below — and if you use the sounds in something you release, the licences here are the ones that travel with them.

The 808 and 909 engines are original models of those machines' circuits rather than recordings of them, and Roland's trademarks belong to Roland.