OctaSine is a new, free, open-source FM synthesizer plugin for macOS, Windows, and Linux, inspired by NI FM8 and Elektron Monomachine. Free, free, free. There has never been such a wealth of high-quality free synthesizer plugins before. I’m absolutely certain. And now, there’s one more worth checking out. This virtual instrument from developer Joakim Frostegård is a new open-source FM synthesizer that won’t cost you a thing. This is a new FM synthesizer plugin with 4 operators (128 voices). inspired by the beloved Elektron Monomachine and Native Instruments FM8. It features four operators with independent parameters such as volume, panning, modulation index, feedback, three different frequency modifiers (ratio, free, and fine-tune), and ADSR envelope parameters. Additionally, it offers a white noise mode.
One of OctaSine’s strengths lies in its flexible routing system. It allows you to set the output operators and the percentage of the signal that is simply added to the final output. By default, it functions like a traditional FM synthesizer (from OP4 to OP3…). With the new option, you can enable additive synthesis. The possibility of modulation panning is also noteworthy.
Features
Four operators
Four FM operators with parameters for wave form (sine, square, triangle, saw and noise), volume, panning, feedback and frequency (ratio, free and fine), with visualizations of stereo wave forms after modulation.
Flexible routing
Flexible routing allows setting the operator modulation targets (with some limitations) as well as the amount of signal that is simply added to the final output, enabling additive synthesis.
Four LFOs
Four LFOs with multiple waveforms, oneshot and loop modes and optional DAW BPM sync. They can target most operator parameters and most parameters of lower-index LFOs.
ADSR envelopes
Each operator is connected to an attack-decay-sustain-release volume envelope with logarithmic slopes. Envelope groups make synchronizing changes a breeze.
Modulation panning
A unique feature of OctaSine is that modulation can be panned, enabling positioning FM within the stereo image. Additionally, true stereo panning is implemented, not just balance.
Cross-platform
Runs on macOS (10.15 or later), Windows 10/11 and Linux (X11 only) in VSTI- or CLAP-compatible DAWs on 64-bit computers. Synthesis is SIMD-accelerated on x86_64 (SSE2, AVX).
