Surge Free Hybrid Synthesizer

Surge Free Hybrid Synthesizer

Surge is a free and open-source hybrid synthesizer available in VST and AU plugin formats for Windows and macOS.


  • Synthesis method: Subtractive hybrid.
  • Each patch contain two scenes which are separate instances of the entire synthesis engine (except effects) that can be used for layered or split patches.
  • Category-based patch browser.
  • MPE support.


  • 3 oscillators per scene.
  • 7 versatile oscillator algorithms: Classic, Wavetable, Window, Sine, FM2, FM3, S&H Noise, and audio input.
  • Classic oscillator is a morphable pulse/saw/dual saw oscillator with a sub-oscillator and hard sync.
  • FM2 and FM3 oscillators consist of a carrier and 2 or 3 modulators and various options.
  • Most algorithms (except FM2, FM3 and Audio input) offer up to 16-voice unison at the oscillator level.
  • Oscillator FM and ring modulation between oscillators 1-3 and 2-3.
  • Most oscillator algorithms (except FM2, FM3 and Sine) are strictly band-limited, yet still cover the entire audible spectrum, delivering a clear punchy yet clean sound.
  • Noise generator with variable spectrum.

Filter Block

  • Two filter units in 8 different configurations.
  • Feedback loop available in 7 of those configurations.
  • Available filter algorithms: Lowpass (12 and 24 dB/oct, each with 3 variations), Lowpass 24 dB/oct (3 variations), Ladder Lowpass (6-24 dB/oct), Highpass (12 and 24 dB/oct, each with 3 variations), Bandpass (12 and 24 dB/oct, each with 3 variations), Notch (12 and 24 dB/oct, each with 2 variations), Comb (4 variations), S&H.
  • Filters can self-oscillate (with excitation) and respond amazingly fast to cutoff frequency changes.
  • Waveshaper (5 shapes).


  • 12 LFO units available, 6 are per voice and 6 are global for the whole scene.
  • DAHDSR envelope generators on every LFO.
  • 7 deformable LFO waveforms + step sequencer.
  • Voice LFOs allow envelope retriggering when used as step sequencer.
  • Fast and flexible modulation routing. Almost every continuous parameter can be modulated.


  • 8 effect units arranged as 2 inserts per scene, 2 sends and 2 master effects.
  • 13 effect algorithms: EQ, Distortion, Conditioner (EQ, stereo image control and limiter), Frequency Shifter, Rotary Speaker, Ring Modulator, Vocoder, Chorus, Phaser, Flanger, Delay, Reverb 1, Reverb 2.

Supported platforms & download

Windows | macOS

Surge Synth Team

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