If you love big, lush, slightly weird 70s polyphonic sounds, this one is a treat. FB-3100 from Full Bucket Music is a free software synth that recreates the Korg PS-3100 polyphonic synthesizer from 1977. The real PS-3100 was a monster of a machine, one of the first fully polyphonic analog synths, with a sound that is warm, rich, and a bit wild around the edges. This plugin gets you that vibe for free, with no hardware, no maintenance, and no second mortgage.
It follows the original pretty closely. You get band limited oscillators with six waveforms, a classic two pole lowpass filter based on the K-35 filter from the hardware, a resonators section made of three bandpass filters that can add that hollow, vocal, almost string machine character, plus two modulation generators, sample and hold, a semi modular patch panel, and micro tuning if you want to get strange. There is also an extra paraphonic envelope generator and MIDI learn, so every knob can be mapped to your controller. It is light on CPU too, which is handy when you want to stack a few instances for huge pads.
Download it free here: https://www.fullbucket.de/music/fb3100.html
How to install it:
Windows: grab the Windows download from the page, unzip it, and copy the VST2 or VST3 file into your usual plugin folder. Rescan your plugins in your DAW and look for FB-3100.
Mac: grab the macOS Universal Binary download from the page and run the installer package. It installs the VST2, VST3, AU, CLAP and AAX versions, so rescan in your DAW and you are good to go.
Linux is not listed for this one, so Windows and Mac only here.
See it in action in this walkthrough:
Honestly, this is one of those freebies that sounds way more expensive than it is. Load up a pad preset, open up the resonators a bit, add a touch of delay, and you are straight into vintage synth heaven. Give it a spin and let me know what you make with it.