Free Software Synthesizers

Organic

Organic is a free software synthesizer developed by Safwan Matni. Available format(s): VST for Windows.

Features:

Simple interface.

Middle Eastern quarter tone adjustability.

ADSR Envelope generator.

Low CPU usage.

http://smatni.tripod.com/safwanmatnivstplugins/

Organ One

Organ One is a free software synthesizer developed by Bojo. Available format(s): VST for Windows.

Features:

16 voice polyphonic.

9 drawbars/2 oscillators in each voice.

LFO with 8 different waveforms (incl. random).

Stereo FX.

Several MIDI-controllers implemented.

http://www.bojo-software.com/

OP-X Free

OPX Free is a free software synthesizer modeled after the Oberheim hardware synthesizer, developed by SonicProjects. Available as VST for Windows.

OP-X Free is a cut down preset version of OP-X offering a small set of selected original OP-X sounds for free use. OP-X Free has got the same basic engine as OP-X while only giving access to a few parameters on a cut-down user interface.

OP-X Free can’t load any further OP-X patches and does not offer automation or MIDI remote control. However, it can be upgraded to OP-X Player, which contains the full OP-X patches library as well as automation and MIDI remote control.

Features:

A small set of selected original OP-X sounds.

Separate Voice Design (SVD).

Comprehensive detuning options.

Tunable: Oscillators, Filters, Envelopes, Portamento times.

Spread knob for unison and polyphonic mode.

SEM-Filter emulation.

Polyphonic portamento.

Individual voice pans.

Direct upgrade knob.

http://www.sonicprojects.ch/

One Track Orchestra

One Track Orchestra is a free software synthesizer developed by make some music now!. Available format(s): VST for Windows.

This is a simple and free VSTi plugin created to help you sketch/prototype your orchestral arrangements and productions in an easy and fast way.

This instrument puts a complete orchestra on a single track of your DAW (so you don’t need to create additional tracks). You can add strings, brass, woodwinds and even percussion at the same time, using only one MIDI channel.

The sounds of the different instruments are mapped on different sections of the keyboard, and they are velocity dependent. The only controls on the GUI are the reverb and volume faders.

This is a free sketching tool, created for songwriting/demo recording, and oriented towards beginners and songwriters who need a simple and fast tool, so it does not include multiple articulations or round robin samples. It is not supposed to be an alternative to big, professional sampled instruments and libraries.

The instrument is provided as-is, with no warranties. 32-bit and 64-bit versions are available. It should work fine on most DAWs. It has beed developed and tested on a Windows 10 PC and it worked fine with Reaper, Tracktion, Studio One, Podium, MuLab and SAVIHost.

This virtual instrument was designed by Luis Valoyes using samples from the VSCO Community Edition. The plugin is powered by Maize Sampler.

http://www.makesomemusicnow.com/

Omaha

Omaha is a free software synthesizer developed by Kriminal. Available format(s): VST for Windows.

Omaha is virtual analogue synth. It was inspired by the Yamaha CS-5.

Features.

1 VCO (saw/pulse) plus white noise generator.

PWM.

1 LFO (high speed) – sine/saw/S+H.

VCF – 12dB LP/HP 6dB BP.

VCA – ADSR.

21 banks of presets.

http://homepage.ntlworld.com/lisa.millington/

OM

OM free software-synthesizer by Softrave

OM is a free software synthesizer developed by Softrave. Available format(s): VST for Windows.

OM synth is for Trance, Rave and Techno. It’s really aggressive and buzzing.

http://www.tikov.com/softrave/softrave.htm

Oktagon

Oktagon is a free software synthesizer developed by Kriminal. Available format(s): VST for Windows.

Features:

8 VCOs, each with independent control over tune/pan/gain.

Saw/Ramp/Tri/Pulse Waveforms (Global).

PWM – LFO/Manual.

Filter Freq LFO.

Pitch/Amp LFO.

LP12/LP24/HP/BP/BR Filter.

Separate ADSR for AMP and ENV.

Poly/Mono (with Portamento).

Global Tune (octave) and Gain.

http://homepage.ntlworld.com/lisa.millington/

OdOrgan

OdOrgan is a free software synthesizer developed by Odo Synths. Available format(s): VST for Windows.

Phase mod.

ADSR for filter and volume.

Mono mode and 3 notes polyphony mode.

32 presets.

Sine/Saw/Pulse/Triangle waveforms.

Rotate.

Percussion.

9 note polyphonic version available.

https://theodosynthsarchive.wordpress.com/

Oddy-Free

Oddy-Free is a free software synthesizer developed by Roberson Audio Synthesizers. Available format(s): VST for Windows.

Oddy-Free is an emulation of an Arp Odyssey Mk.II – much attention to detail was given in the layout of the signal path to have it behave as accurately as possible. It does have just a touch more umph than most originals would – this particular emulation was based on the “illegal” filter versions based on Moog’s -24dB Low-Pass filter, so it sounds quite a bit smoother and richer but at the same it can produce the harsh metallic tones known from the Odyssey.

http://www.robersonaudio.com

Oddly Organ

Oddly Organ is a free software synthesizer developed by Odo Synths. Available format(s): VST for Windows.

Oddly Organ is a percussion organ.

Features:

A simple EQ.

ADSR for Filters and Volume.

Tracking Cutoff and Resonance.

A Key Click effect.

2 simple Chorus effects.

A Tremolo.

A rotate Fx but it’s not a real rotator.

Distortion.

Retrigger Glide and Mono mode.

https://theodosynthsarchive.wordpress.com/