Six Sines, RRV-10, State Machine Playtime: Free Plugins of the Week
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Six Sines, RRV-10, State Machine Playtime: Free Plugins of the Week · Source: BaconPaul
Six Sines is an awesome open-source FM synth by BaconPaul – one of the developers of the Surge synthesizer. This week’s collection of free plugins also features a recreation of a classic Boss reverb unit and a fun instrument based on children’s toys.
Free Plugins of the Week
BaconPaul Six Sines: Free 6-Operator FM Synth
BaconPaul is best known for his work on Surge XT, the fantastic open-source hybrid synth. As a side project to get him started in 2025, he recently released Six Sines, a free FM synth inspired by the famous Yamaha TX81Z (the Lately Bass synth!).
Despite the name, the six operators can produce a variety of other waveforms in addition to sine waves, most notably the original waveforms from the TX81Z. Each operator can output audio or modulate itself or subsequent operators. You can choose between phase modulation and digital ring modulation / AM. There’s a clearly laid-out matrix for setting up inter-operator modulation, and each node even gets its own envelope and LFO. That’s some powerful stuff right there, just listen to this awesome demo track by Kinsey Dulcet:
Six Sines also includes six macros for modulating several parameters at once, and you can also map external MIDI modulators (including MPE) to any parameter.
Like any FM synth, Six Sines doesn’t provide the same kind of immediacy you’d expect from a subtractive-style synth, but once you get the hang of it, it’s capable of some very cool and classic FM sounds.
Six Sines is available for macOS, Windows, and Linux in VST3, AU, and CLAP formats and as a standalone app.
giulioz RRV-10: Free Emulation of a Classic Boss Reverb
Following up on RdPiano, developer giulioz is back with another open-source project inspired by a bunch of classics from the 80s. Once completed, smol-rack will include emulations of the Boss Micro Rack series effects, or at least those that were digital.
RRV-10 is the first in the series. The plugin emulates the Boss reverb unit of the same name. According to giulioz, he used an emulation of the original HG61H20R36F chip to precisely reproduce the sound of the original.
Like the hardware unit, the RRV-10 plugin gives you a choice of nine modes: two rooms, two halls, two plate reverbs, two multi-tap delays, and a gated mode – indispensable for those 80s vibes. You can adjust the decay time and apply some pre-reverb EQ for sound shaping.
The developer is also working on emulations of the RCE-10 Chorus/Ensemble, RDD-10 Digital Delay, RSD-10 Sampling Delay, RPD-10 Panning Delay, and RPS-10 Digital Pitch Shifter, which are in varying states of completion.
RRV-10 is currently available for macOS and Windows in VST and AU formats.
Cradle State Machine Playtime: Make Music with Toys
Cradle has added another instrument to the free State Machine series. State Machine Playtime is a sample-based instrument based on children’s musical toys. But as it also includes extensive tone shaping tools, it can deliver a wide range of sounds far beyond child’s play.
State Machine Playtime lets you layer and blend two samples from the library. Each layer gets a complete synth engine with a filter, amp, LFO, and a couple of envelopes. There’s also a good selection of audio FX for sound shaping (EQ, bitcrusher, delay, bad speaker, reverb), as well as scale and chord modes and an arpeggiator. The plugin comes with 40 presets.
State Machine Playtime is available for macOS and Windows in VST3, AU, and AAX formats.
Looking for more free plugins like Six Sines, RRV-10, and State Machine Playtime? Check out our archive!
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One response to “Six Sines, RRV-10, State Machine Playtime: Free Plugins of the Week”
Can someone post an easy to find download link for the PC .exe file of Six Sines? The GitHub website makes it impossible to find the download link. Thx.