homecrate synth — Dual-Oscillator AUv3 Instrument

homecrate synth is a polyphonic software synthesizer you can load as an AUv3 instrument inside Homecrate (or other hosts). It pairs two independent oscillators with per-oscillator amp envelopes and filters (linkable for unified control), a multimode filter, dual ADSR envelopes, two assignable LFOs, per-voice IR cabinet convolution, a built-in arpeggiator, character profiles for analog-style voice drift, external audio mode, MPE support, and a built-in effects section (bit crusher, chorus, delay, reverb). A slide-up piano keyboard lets you audition patches without a MIDI controller.

🟢 New to subtractive synths? Jump to Quick Start, then skim The Interface so the knob labels map to what you see on screen.

🔵 Already know ADSR and LFOs? The signal flow is: OSC A + OSC B (each with independent envelope/filter, or linked) → blend crossfader → per-voice IR cabinet → effects. Voice mode (poly vs mono unison), arpeggiator, and per-osc tuning live in the oscillator header row.

Quick Start

Load homecrate synth as an AUv3 instrument on an audio track in Homecrate (see Loading & Removing Plugins)
Route a MIDI track to the plugin using the AUv3 instrument picker on the MIDI channel strip (see Instrument Plugins & MIDI Routing)
Tap the patch name button under the title to open Patches — start from Init Patch or load a saved program
Tap the piano keys icon to show the on-screen keyboard and play a few notes
Turn OSC A and OSC B waveforms, then adjust CUT (filter cutoff) and RES (resonance)
Enable the arpeggiator and try HOLD mode with direction Up or Random for classic synth sequences

Loading homecrate synth in Homecrate

homecrate synth appears under the Instruments tab in the Plugin Browser. After you load it, use MIDI from the piano roll, an external keyboard, or the built-in keyboard overlay to play notes.

If Homecrate Pro is not active, a Pro banner appears at the top of the plugin (same pattern as Homecrate Drum and homecrate amp). Unlocking Pro removes the banner for all Homecrate apps that share the entitlement.

The Interface

[SCREENSHOT: Full homecrate synth — header, oscillators, arp, envelopes, IR cabinet, character, filter, LFOs, effects]

The layout scrolls vertically:

Header — branding, patch manager button, PASTE button, MASTER gain, PAN, keyboard toggle
Oscillators — voice mode (poly / mono), MPE button, optional unison and glide in mono, global pitch bend range, velocity sensitivity, LEVEL, OSC A and OSC B cards
Blend — A VOL and B VOL knobs flanking a DJ-style crossfader between oscillators
Arpeggiator — inline panel with enable/latch toggles, mode selector (HOLD/CHORD/SEQ), rate, gate, direction, octave range, and 8-step sequencer grid
Voice Mode & Allocation — poly voice count or mono unison settings; voice stealing and priority modes (poly only)
IR Cabinet — two side-by-side slots (CAB Even / CAB Odd) for per-voice impulse response convolution with gain and 3-band EQ
Envelopes — AMP ENV and FILT ENV (ADSR) with visual curves and link toggles for per-oscillator independence
Character + LFOs — side-by-side: Character drift panel (poly only) and LFO 1 / LFO 2 blocks
Filter + Effects — side-by-side: Filter column (type, cutoff, resonance, envelope amount, key tracking) and Effects grid (Crush, Chorus, Delay, Reverb)
Microtonal Tuning — optional EDO and world scale presets

[SCREENSHOT: Header — patch button, Paste button, Master, Pan, keyboard]

Control	What it does
Patch line (e.g. `01 - Init Patch`)	Opens the Patches sheet: save a new program by name, load from the list, or swipe to delete. Saved patches are sorted alphabetically; slot numbers in the list reflect that order.
PASTE	Paste a preset from the clipboard (JSON format). Requires Homecrate Pro.
MASTER	Overall output level of the instrument
PAN	Stereo pan
Piano keys	Toggles the floating keyboard overlay at the bottom of the screen. When active, the icon highlights in mint.

Oscillators and voice mode

[SCREENSHOT: Oscillator section — POLY/MONO, MPE button, optional UNI/DET/GLD, OSC A and OSC B cards]

Poly vs mono

POLY — classic polyphonic playing. A VOC (voice count) knob appears so you can limit maximum voices.
MONO — single-voice legato-style behavior. UNI (unison count), DET (unison detune), and GLD (glide time) appear for stacked detuned voices and glide between notes.

MPE button

Tap MPE to open the MPE Settings sheet. Enable MPE mode for per-note pitch bend, pressure (Y-axis), and slide (Z-axis/CC74) modulation. Configure pitch bend range (1–96 semitones, default 48) and route Y/Z axes to filter cutoff, amp envelope amount, oscillator shapes, or LFO depth. MPE is off by default.

Shared header knobs

Knob	Label	Purpose
BND	Pitch bend range	How far the host pitch wheel bends pitch, in semitones
VEL	Velocity sensitivity	How strongly note velocity affects dynamics
LEVEL	Osc master level	Overall level before the filter (per oscillators group)

In mono with unison greater than one, a row of V1 … Vn knobs appears — these set per-voice shape offsets for the unison stack.

OSC A and OSC B

Each oscillator card includes:

Control	Label	Purpose
Waveform	—	Selects the oscillator waveform (see the horizontal waveform selector in the UI)
OCT	Octave offset	Coarse octave shift (-3 to +3 octaves)
CRS	Coarse tune	Semitone detune vs the played note
FINE	Fine tune	Sub-semitone detune for thickening or slight chorus between A and B
SHP	Shape mod	Waveshaping / harmonic shaping amount (waveform-dependent)

Per-oscillator independence

By default, the amp envelope, filter, and filter envelope are linked between oscillators (both use the A-side settings). Each section has a link toggle that can be disabled to configure oscillators independently:

Amp Envelope Link — unlink to give Osc B a slow attack while Osc A punches in immediately
Filter Link — unlink to run LP on Osc A and BP on Osc B simultaneously
Filter Envelope Link — unlink for different filter modulation curves per oscillator

When re-linking, Osc B parameters snap to match Osc A.

Blend (A / B)

[SCREENSHOT: Blend row — A VOL knob, crossfader, B VOL knob]

A DJ-style crossfader mixes OSC A vs OSC B. A VOL and B VOL rotary knobs flank the crossfader to set pre-blend levels. At center position, both oscillators contribute equally; slide fully left or right to isolate one oscillator. The crossfader thumb is a black rectangle with a white center line.

Arpeggiator

[SCREENSHOT: Arpeggiator panel — enable, latch, mode buttons, rate/gate/direction controls, sequencer grid]

The arpeggiator intercepts incoming MIDI notes and schedules gated note events according to the selected mode, rate, and pattern. It sits between the blend row and the voice mode section.

Control	Purpose
ENABLE	Toggles the arpeggiator on/off
LATCH	When on, the arp continues playing after you release all keys. Tap new keys to start a fresh pattern.
Mode buttons	HOLD (classic up/down/random arp), CHORD (whole chord per step, cycling through octaves), SEQ (programmable 8-step sequencer)
RATE	Note division: 1/4, 1/4T, 1/8, 1/8T, 1/16, 1/16T, 1/32 (relative to project tempo)
GATE	Note length as a fraction of the step duration (0.05–1.0). At 1.0, notes are legato; lower values create staccato.
DIR	Direction for HOLD mode: Up, Down, UpDn (up-down bounce), Rnd (random)
OCTAVES	How many octaves to span (1–4). In HOLD mode, the arp cycles through your held notes across octave shifts. In CHORD mode, each step plays the chord transposed up by one octave.
RANDOM OCT	(CHORD mode only) Randomize the octave on each step instead of cycling sequentially.
STEPS	(SEQ mode only) Number of active steps in the sequencer (1–8)

Sequencer (SEQ mode)

When SEQ mode is active, an 8-step grid appears. Each step shows its pitch (C–B chromatic) and octave offset (−2 to +2).

Tap a step to toggle it on/off. Enabled steps highlight; disabled steps are grayed out.
Long-press a step to open the step editor sheet where you can set chromatic pitch (C, C#, D…) and octave offset.
The sequencer plays only enabled steps. The currently playing step is outlined in green.
Pitch is relative to the held note(s). If you hold C4, a step set to “E, +1” plays E5.

Envelopes

[SCREENSHOT: AMP ENV and FILT ENV with ADSR knobs, curves, and link toggles]

Envelope	Controls	Typical use
AMP ENV (A-side)	Attack, Decay, Sustain, Release	Shapes overall loudness over time for Osc A (or both if linked)
AMP ENV (B-side)	Attack B, Decay B, Sustain B, Release B	Independent loudness envelope for Osc B (visible when Amp Env Link is disabled)
FILT ENV (A-side)	Attack, Decay, Sustain, Release	Modulates the filter (together with ENV amount on the filter) for Osc A (or both if linked)
FILT ENV (B-side)	Attack B, Decay B, Sustain B, Release B	Independent filter envelope for Osc B (visible when Filt Env Link is disabled)

The UI shows ADSR curves next to the knobs for quick visual feedback. Each envelope section has a link toggle icon. When linked (default), only the A-side controls appear and both oscillators use the same envelope. When unlinked, both A and B controls appear side-by-side.

Filter

[SCREENSHOT: Filter column — LP/HP/BP buttons, CUT, RES, ENV, KEY knobs]

Control	Purpose
LP / HP / BP	Low-pass, high-pass, or band-pass mode (A-side, or both if linked)
CUT	Filter cutoff frequency (A-side, or both if linked)
RES	Resonance (emphasis around the cutoff) (A-side, or both if linked)
ENV	How much the FILT ENV opens or closes the filter (A-side, or both if linked)
KEY	Keyboard tracking — how much MIDI note pitch shifts the cutoff (A-side, or both if linked)

When the Filter Link toggle is disabled, independent B-side controls appear: LP/HP/BP B, CUT B, RES B, ENV B, KEY B. This allows you to run different filter types (e.g., LP on A, BP on B) or different cutoff/resonance settings per oscillator.

IR Cabinet

[SCREENSHOT: IR Cabinet section — CAB Even and CAB Odd cards side-by-side]

Per-voice impulse response convolution. Two slots (CAB Even / CAB Odd) alternate across voices in poly mode: even-indexed voices route through Slot A, odd through Slot B. Load different cabinet IRs on each slot so every alternating chord note gets a different cabinet character.

Each slot card includes:

Control	Purpose
Power icon	Bypass toggle (green when active)
IR file button	Opens the IR picker. Tap Browse Files… to import from the file system (requires Homecrate Pro) or select from the existing library.
X button	Clears the loaded IR and disables the slot
VOL	Cabinet gain (0–2x)
LO / MD / HI	3-band EQ: Low shelf @ 80Hz, Mid peak @ 800Hz, High shelf @ 8kHz (±12dB each)

Supported IR formats: WAV, AIF, AIFF, CAF, MP3, M4A. Files are automatically resampled and downmixed to mono on load. IRs are stored in the shared HomecrateSamples/IR/ library (same files as homecrate amp).

Character

[SCREENSHOT: Character panel — TUNE, FILT, SHP, GAIN knobs, SEED knob, REROLL button]

Per-voice character profiles create analog-like variation across a chord. Each voice gets small but audible deviations from the nominal patch. Poly mode only — in mono, use the per-unison shape knobs instead.

Control	Range at 1.0	What it does
TUNE	±8 cents	Per-voice pitch drift
FILT	±15%	Per-voice filter cutoff multiplier
SHP	±0.15	Per-voice waveshape offset
GAIN	±2 dB	Per-voice amplitude variation
SEED	0–99	Changes the pseudo-random pattern for all drift amounts

All defaults are 0.0 (clean/modern sound). Deterministic LCG hash from voiceIndex × seed ensures stable variation across note-ons. The REROLL button increments the seed to audition different patterns.

LFOs

[SCREENSHOT: LFO 1 and LFO 2 rows, sharing a panel with Character]

Two identical LFO blocks (LFO 1, LFO 2) sit side-by-side with the Character section. Each has:

Control	Purpose
RATE	LFO speed
DEPTH	Modulation depth
Shape	SIN, TRI, SAW↑, SAW↓, SQR, S&H
Destination	OFF, FILTER, A PIT, B PIT, BLEND, AMP, PAN, A SHP, B SHP — what the LFO modulates

Use FILTER destination for classic wobble; A PIT / B PIT for vibrato on one oscillator; BLEND for timbre motion between oscillators. LFO filter cutoff modulation applies to both Filter A and Filter B (whether linked or unlinked).

Effects

[SCREENSHOT: Effects grid — Crush, Chorus, Delay, Reverb]

Post-IR, all voices are mixed and pass through the effects chain in order: Bit Crusher → Chorus → Delay → Reverb → Master Gain/Pan.

Crush

Knob	Purpose
MIX	Dry/wet
BITS	Bit depth reduction
RATE	Down-sampling / lo-fi rate

Chorus

Knob	Purpose
RATE	Modulation speed
DEPTH	Modulation depth
MIX	Dry/wet

Delay

Control	Purpose
Sync	1/4, 1/8, 1/16, dotted and triplet variants — note division vs project tempo
FDBK	Feedback / repeats
MIX	Dry/wet

Reverb

Knob	Purpose
DECAY	Tail length
SIZE	Room size
PRE	Pre-delay (ms)
MIX	Dry/wet

External Audio Mode

[SCREENSHOT: External Audio toggle in settings]

Bypasses oscillators and processes external audio input (from the host’s audio routing) through the A-side amp envelope and filter. Useful for gating, filtering, or applying synth effects to external sources.

Control	Purpose
Mode	0 = off (normal synth), 1 = external audio pass-through
VCA Bypass	When off, MIDI gates the VCA (notes trigger the envelope). When on, audio passes through continuously.
Input Gain	0–2x, default 1.0

MIDI note-on events still trigger the amp envelope (unless VCA Bypass is on), so you can gate external audio with the piano roll or keyboard.

Patches

Open the patch manager from the patch name button.

Save — Type a new name and tap Save to store the current parameter state (includes all 313 parameters: oscillators, envelopes, filters, IR slots, arpeggiator settings, character, effects, and more).
Load — Tap Load next to a row to recall that program (the sheet dismisses).
Delete — Swipe left on a row to remove a saved patch.

The main screen’s patch line shows either 01 - Init Patch or a numbered slot with the active program name.

On-screen keyboard

When enabled, a keyboard overlay sits at the bottom of the plugin. It sends note on/off to the synth engine using the same routing as external MIDI — useful for programming sounds on the go. If the arpeggiator is enabled, keyboard notes are intercepted by the arp controller first.

Signal flow summary

                    ┌─────────────┐
                    │  MIDI Note  │
                    │  (or Arp)   │
                    └──────┬──────┘
                           │
                  ┌────────┴────────┐
                  ▼                 ▼
            ┌───────────┐     ┌───────────┐
            │   Osc A   │     │   Osc B   │
            │ +octave   │     │ +octave   │
            │ +tune     │     │ +tune     │
            │ +shape    │     │ +shape    │
            └─────┬─────┘     └─────┬─────┘
                  ▼                 ▼
            ┌───────────┐     ┌───────────┐
            │  Vol A    │     │  Vol B    │
            └─────┬─────┘     └─────┬─────┘
                  ▼                 ▼
            ┌───────────┐     ┌───────────┐
            │ Amp Env A │     │ Amp Env B │
            │  (ADSR)   │     │ (or linked)
            └─────┬─────┘     └─────┬─────┘
                  ▼                 ▼
            ┌───────────┐     ┌───────────┐
            │ Filter A  │     │ Filter B  │
            │ LP/HP/BP  │     │ (or linked)
            │ +Filt Env │     │ +Filt Env │
            └─────┬─────┘     └─────┬─────┘
                  │                 │
                  └────────┬────────┘
                           ▼
                    ┌─────────────┐
                    │   Blend     │
                    │  A ⟷ B     │
                    │ (crossfader)│
                    └──────┬──────┘
                           ▼
                  ┌─────────────────┐
                  │  IR Cab Slot    │
                  │  (per-voice)    │
                  │  Even → Slot A  │
                  │  Odd  → Slot B  │
                  │  + Gain + 3-EQ  │
                  └────────┬────────┘
                           ▼
                    (Voice Output)
                           │
        ┌──────────────────┴──────────────────┐
        │         All voices mixed             │
        └──────────────────┬──────────────────┘
                           ▼
        ┌──────────────────────────────────────┐
        │        Effects Chain                  │
        │  Crush → Chorus → Delay → Reverb     │
        └──────────────────┬──────────────────┘
                           ▼
                  ┌─────────────────┐
                  │  Master / Pan   │
                  └────────┬────────┘
                           ▼
                     Stereo Out

Tips

Start from Init Patch, set OSC B to a different waveform than OSC A, then sweep the crossfader — small FINE offsets between oscillators add width
Keep FILT ENV decay shorter than AMP ENV decay for punchy plucks; match them for pad sounds
Assign LFO 1 to FILTER at low RATE and moderate DEPTH for a slow sweep; use S&H on BLEND for random texture
In MONO with unison, increase DET slightly before UNI count for a stacked analog-style lead
Use Delay sync divisions that match your project tempo for dotted-eighth echoes; keep MIX low so the delay sits behind the dry synth
Arpeggiator HOLD mode with direction Random and octave range 2–3 creates generative sequences from simple chords
Arpeggiator CHORD mode with RANDOM OCT on makes stab patterns less predictable
Arpeggiator SEQ mode lets you program melodic patterns: set step count to 4 or 8, long-press each step to dial in pitch intervals, then hold a root note to transpose the whole sequence
Load different IR cabinet files on CAB Even and CAB Odd so each voice in a chord gets a unique cabinet character — try a bright cab on even voices and a darker cab on odd voices
Character profiles add analog warmth: start with TUNE at 0.3 and FILT at 0.2 for subtle chord variation, or crank all knobs to 1.0 for a vintage polysynth sound

Next steps

General plugin loading: Loading & Removing Plugins
MIDI routing in the DAW: Instrument Plugins & MIDI Routing
Editing MIDI clips: The Piano Roll Editor