BaconPaul has released Six Sines, a free and open-source plugin inspired by the TX81Z FM synth module.
FM synthesis is a somewhat divisive topic; some love it, some hate it, and others don’t understand all the fuss.
There’s no denying the power of FM synthesis, even if synths like the Yamaha DX7 gained fans and turned enthusiasts away equally.
Thankfully, things have moved on since the DX7, which had a notoriously convoluted workflow that would test the patience of angels.
Whether you love digital FM’s distinct character or find it too cold and harsh, the conversation never ends.
The recent release of Behringer’s BX1 (DX1 clone with CS-80-inspired filters) has the topic trending again, making it an ideal time for BaconPaul’s Six Sines.
BaconPaul is part of the awesome team behind Surge.
Six Sines is a free, open-source MPE-compatible, 64-voice, six-operator FM synth plugin for macOS, Linux, and Windows.

The interface provides a straightforward workflow that lets you start making interesting sounds immediately.
The top row of the GUI is where you can adjust each of the six operator ratios.
Clicking on any of these ratio controls will open a corresponding panel at the bottom of the interface, where you can select waveform types and set their phase, adjust a DAHDSR envelope, a multi-wave LFO, pitch, and modulation.
Sandwiched between the ratio controls and the bottom panel is an FM modulation matrix and operator mixer with individual level/pan controls (Main Level, Pan, and Tune controls are just above).
Waveshapes include sine, squarish, swish, and the original Yamaha TX81Z waveforms. The original Yamaha TX81Z waveforms have been revived recently, including Sonicbits Exakt late in 2024.
Six Sines comes to life through modulation; each operator can output audio, modulate itself, or subsequent operators.
“Each operator, operator modulation application, operator feedback, and operator level can be independently and individually modulated.”
Six Sines is currently in version 1.0.4 and receiving regular updates from the developer.
The plugin is available in AU, VST3, and CLAP formats for macOS, Windows, and Linux.
Returning to the Behringer BX1 for a second, how do you feel about the clone-after-clone strategy?
I can understand the strong reactions within the industry, but I’m always surprised at how much they offend some retail customers (albeit a minority, but it seems strange to me).
Download: Six Sines (FREE)
More:
25 Comments
Holger Rohling
on“BaconPaul has released Six Sines, a free and open-source TX81Z that was inspired by the FM synth plugin.”
Isn’t it exactly the other way round…? :-)
Tomislav Zlatic
onYou’re correct – I probably messed up this part while editing the article. 🤦 Thanks for noticing!
Frits van Zanten
onHow does this compare to, say, FM8 and Ableton’s Operator?
Does ‘revive’ mean you can get and load TX81Z presets?
Numanoid
onThe interface reminds me of that golden oldie Oxe FM Synth
Alex
oneach note is adding about 20% cpu usage lol
Mark
onI downloaded and tested the Linux version which runs fine. The sounds from the presets are quite good, overall I think the plugin sounds good (according to the presets). However, I think I am too stupid to operate that thing and it has quite a steep learning curve (for me). I would be thankful for a in-depth video and tutorial.
Numanoid
onGoogle “John Chowning” and Yamaha DX7 ;-)
Frits van Zanten
onI think an instructional video on FM8 might be helpful. I shows a similar matrix structure. Maybe before that a more general video on the ‘practical’ principles of FM, the general idea. The simplest one is FM. The basics by Andrew Huang. It will pay off. After those you will get the general idea and mostly understand what this plugin does.
Mark
on@numanoid
@Frits
Thank you very much, very good hints and directions to start with! Highly appreciated!
Caleb
onThis is great, but in my opinion it desperately needs a filter to keep some of the high harmonics in check. One per-operator would be ideal, but I’d still take a global lowpass.
MRugaW
onMy sentiments exactly. I would have picked this up if it had some standard FX (EQ/Filters, Saturation/Distortion, Delay/Reverb, Modulation e.t.c.)
Calidreads
on…nicht schlecht und der klang ist auch ok :-)
Leider ist die standalone nicht skalierbar , hat man kein zugriff auch das gesammtgen plugin .
Aber ok inside meine Daws ( Cubase und Sequoia ) funzt dat olug super und der Gui ist auch angepasst :-)
Danke BpB und Baconbro :-)
mrg
onAbout clones. Huge topic, but I’ll try to summarize a thought or two. I’m fine with it. Software or hardware, it’s always a bit of a different flavour, different take on the original anyway, so an update, upgrade sometimes on the original. Progress, and that is good, always.
On Behringer in particular. They’re reviving machines that aren’t built anymore, quite close to the originals or at least as much as they can nowadays. The pricing looks very decent, and based on the manufacturing, not the 2nd hand market quotes. They’re not the first nor the last of making clones either,
Everyday more humans are on this planet of ours. We’re gonna need MOAR synthesizers to put into those hands. I will never shame Behringer, or any clone maker, for giving moar people access to, cheap but decent and affordable musical tools.
On a moar general note concerning copyrights and IPs (Intellectual Property). While I reckon that credit should be given to people inventing new stuff, or expanding upon them, you should also take into consideration that very fast, (c) and IP are properties of corporations and not the original people anyway. The days of the single individual in a garage are over…
TL;DR: Give Behringer a break, they’re not the ones destroying lives right now.
*CLANG* FRED? WHAT THE F…?
Mugani So
onHow is BPB on a rampage deleting half of the comments, but then they leave this up?
Tomislav Zlatic
onBPB is not on a rampage deleting comments. :)
We removed three comments in one thread to stop a flame war (insulting other BPB readers is not allowed) and 20+ comments from a single poster on another thread (it was unintentional spamming).
As far as I see, there is no reason to remove the comment you are referring to.
mrg
onI am the Bringer of Chaos and Mayhem. Sowwy… :’-(
Tomislav Zlatic
onYou are the Behringer of Chaos (j/k)! :)
mrg
onTHAT’S ME! \o/
mrg
onI said something that triggered you? Please, tell me what… I might even agree to parts of it, you know. It’s a complex issue.
Numanoid
onSteinberg Backbone is free with paid purchases at Plugin Boutique in February
Pitch Innovations’ Rhythm Box sequencer is free with paid purchases at ADSR sounds
Synthwave library “Power Move” for Kontakt is free with paid purchases at Audio Plugin Deals
viceverser
onLove BaconPaul’s stuff, ever since I knocked around the Surge Discord, this thing sounds nice, my only problem (I hope will be sorted in update) is it’s a really tall GUI, that’s hard to manage on my PC, unusable in FL Studio… I’d really dive in if I could shrink it a bit, will eagerly wait for update.
Thanks for a new bit of kit Paul, you’re awesome as always.
sam
onis loopcloud no longer making the monthy giveaway for new subscribers?
Numanoid
onW.A. Production’s Music Producer Marketing Motivation & Mindset Vol 4 is a free PDF book, a self-help guide for the budding pro musician
Mark
onyou can get a cool CS-80 inspired VSTi named “Unstable” free at mophoice dot com, one click download for windows and mac. I tested it in reaper linux bridged via yabridge, and it works very well, and sounds very nice and is easy to operate. Layout and Gui look practical and nice. I have no CS-80 1st hand experience, but it gives me instant 80ies vibes. I like the Pad and 80s lead sounds quite much which I could dial in very easy. There some presets, too.
morphoice (dot) com/plugins
Leuchtkraft
onSounds good, runs without problems and automatisation in ableton works fine. Nice thing. Big thanks for making that