OS-251
size 2 MB / 7 MB / 4 MB
OS-251 is a pure digital lo-fi synthesizer.
The oscillator has alias noise (specific to digital signal processing) famous on classic samplers like E-mu SP-12 which adds lo-fi feeling to the sound. You can enjoy the powerful sound at modern sampling rates with your DAW.
- Up to 10 voices of polyphony.
- Oscillators (Sin, Square, Saw), with Shape parameter.
- Square sub oscillator.
- Noise oscillator.
- Biquad low-pass filter (LPF) with Frequency and Resonance parameters.
- Biquad high-pass filter (HPF) with Frequency parameter.
- Envelope generator which can control LPF and amplitude.
- Low-frequency oscillator (LFO) which can control LPF, amplitude, and Shape parameter.
- LFO sync.
- Chorus.
- Flexible pitch controls (pitch bend width, octave, semitone, fine tuning).
- VST3 / AU.

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OS-251-Windows ( 2 MB )
OS-251-macOS ( 7 MB )
OS-251-Linux ( 4 MB )
We’re audio producers and sound designers with over 20 years of experience in the industry. Our team has lived through the entire evolution of digital audio production.
Our mission? To filter out the junk and bring you only the studio-ready free VSTs that actually compete with paid gear. We do the digging so you can focus on creating.






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