4OSC Synth

The 4OSC Synth is a four-oscillator subtractive synthesizer provided by the Tracktion Engine. It offers a full synthesis signal path with oscillators, filters, envelopes, LFOs, effects, and an internal modulation matrix.

Overview

The 4OSC interface is organized into six tabs:

Tab	Content
OSC	Four oscillators with wave shape, tuning, level, pulse width, detune, spread, pan, and unison voices
Filter	Multimode filter with cutoff, resonance, key tracking, velocity, and a dedicated filter envelope
Amp	Amplitude envelope (ADSR) with velocity sensitivity and analog mode
Mod Env	Two modulation envelopes with ADSR controls and mod destination assignments
LFO	Two LFOs with wave shape, rate, depth, tempo sync, and mod destination assignments
FX	Built-in distortion, reverb, delay, and chorus effects

OSC Tab

Each of the four oscillators has:

Parameter	Description
Wave Shape	Sine, triangle, square, sawtooth, pulse, noise
Tune	Coarse tuning in semitones
Fine	Fine tuning in cents
Level	Oscillator volume in dB
Pulse Width	Pulse width for pulse/square waves
Detune	Unison detune amount
Spread	Stereo spread of unison voices
Pan	Stereo position
Voices	Number of unison voices

Below the oscillators are global controls:

Parameter	Description
Mode	Mono, Legato, or Poly voice mode
Voices	Maximum polyphony (poly mode)
Legato	Legato glide time
Master Level	Master output level in dB

Filter Tab

A multimode filter with its own envelope:

• Type — Low-pass, high-pass, band-pass, notch
• Slope — 12 dB or 24 dB per octave
• Freq — Cutoff frequency
• Resonance — Filter resonance
• Key Track — How much the cutoff follows the note pitch
• Velocity — How much velocity affects the cutoff
• Amount — Filter envelope depth

The filter envelope has independent Attack, Decay, Sustain, and Release controls.

Amp Tab

The amplitude envelope shapes the volume of each note:

• Attack, Decay, Sustain, Release — Standard ADSR
• Velocity — How much velocity affects the volume
• Analog — Adds subtle per-voice variation for an analog feel

Mod Env Tab

Two modulation envelopes (Env 1 and Env 2) that can be routed to any synth parameter via the internal mod matrix. Each has Attack, Decay, Sustain, and Release controls.

Assigning Mod Envelope Destinations

Below the envelope controls, use the + Env 1 and + Env 2 buttons to assign a modulation destination:

1. Click + Env 1 (or + Env 2)
2. Select the destination parameter from the dropdown
3. Click Add
4. Drag the depth slider to set the modulation amount (-100% to +100%)
5. Click X to remove an assignment

LFO Tab

Two LFOs with independent controls:

Parameter	Description
Wave	Sine, triangle, square, sawtooth, sample & hold, noise
Rate	LFO speed
Depth	LFO intensity
Sync	Lock rate to project tempo

Assigning LFO Destinations

Below the LFO controls, use the + LFO 1 and + LFO 2 buttons to assign modulation destinations. The workflow is the same as for mod envelopes:

1. Click + LFO 1 (or + LFO 2)
2. Select the destination parameter from the dropdown
3. Click Add
4. Drag the depth slider to set the modulation amount (-100% to +100%)
5. Click X to remove an assignment

Each assignment appears as a row showing the source and destination (e.g. "LFO 1 > Filter Freq") with a depth slider.

FX Tab

Built-in effects that can be toggled on or off independently:

Effect	Parameters
Distortion	Amount
Reverb	Size, Damping, Width, Mix
Delay	Feedback, Crossfeed, Mix
Chorus	Speed, Depth, Width, Mix

Internal Modulation vs Track Modulators

The 4OSC's internal mod matrix (LFO and Mod Env assignments) operates inside the synth's audio processing. This is separate from MAGDA's track-level modulators, which are external LFOs and curves that can target any device parameter on the track.

Both systems can be used simultaneously — for example, you might use the 4OSC's internal LFO 1 for filter wobble while using a track-level LFO for panning.