Read the Comparison to FF1.
Read the Manual. Click the outline (3 dashes) menu for table-of-contents.

See FF2 on KVR.
See Quick feature overview.
See host_test for host compatibility tests.
See demo for feature tests, and some nice demos along the way.

Legal

https://github.com/free-audio/clap

VST is a trademark of Steinberg Media Technologies GmbH, registered in Europe and other countries.

Download

See the Releases section.

Install

• Remove the previous version (if any) from your VST3/CLAP plugin folder.
  All of it, entire folder, not just the binary.
• Copy the new version folder to your VST3/CLAP plugin folder.
  The entire folder, not just the binary.

Build From Source

• Git clone recursive
• Build scripts are in /scripts: build_windows.bat/build_linux.sh/build_mac.bat
• build_xyz Debug|RelWithDebInfo|Release (0|1):(warn as error) (0|1):(enable asan)

Platform Support

• Windows 10+, X64
• MacOS 10.15+, X64/ARM
• Linux X64, glibc 2.35+
• Linux ARM64 known to work, not officially supported

Host Support

Tested on Carla, Bitwig, Ardour, FLStudio, Reaper and Renoise.
It should work ok on others as well (f.e. known to work on QTractor).

Unfortunately Renoise is not officially supported because of
https://forum.renoise.com/t/saved-automation-data-does-not-respect-vst3s-parameter-id/68461.
You can use it as long as you don't update the plugin (read: install once, and never again).
Updating the plugin might or might not work, but in any case, it's dangerous.

If your dead-set on using Renoise, after installing a new version of the plugin,
load an existing project and check the logfile.
If it says "Parameter indices are stable" (everywhere), all good.
If it says "PARAMETER INDICES HAVE CHANGED" (anywhere), need to re-check your automation lanes.
You can use the menu option "Dump ParamList" to compare what params are on old and new indices.

Relevant Directories

Plugin Folder

• Mac: /Library/Audio/Plug-ins/VST3, /Library/Audio/Plug-ins/CLAP (global)
• Linux: /usr/lib/vst3, /usr/lib/clap (global), $HOME/.vst3,$HOME/.clap (user)
• Windows: Program Files/Common Files/VST3, Program Files/Common Files/CLAP (global)

The exact rules are laid out here for VST3.
I haven't checked for CLAP, but I would be surprised if they are any different.

User App Data Folder

Currently only stores the logfile.
This is whatever JUCE decides it should be, adjusted for XDG_CONFIG_HOME on Linux.
See https://docs.juce.com/master/classjuce_1_1File.html and search for "userApplicationDataDirectory".

For me, it is:

• Linux: ~/.config/Sjoerd van Kreel/Firefly Synth 2
• Mac: /users/USERNAME/Library/Sjoerd van Kreel/Firefly Synth 2
• Windows: C:\Users\USERNAME\AppData\Roaming\Sjoerd van Kreel\Firefly Synth 2

Known Issues

• String oscillator responds to sample rate, but it shouldn't.
  Pitch is good, timbre is not. Long-standing issue, might prove difficult.
• Looks like FLStudio and FF2 disagree on what the default value for MIDI modwheel/pitchbend should be. This causes clicking which you can get rid of by disabling MIDI modwheel/pitchbend sources in the global mod matrix (PB is on by default). If you actually do need and use it, let me know how it fares.
• "Show Manual"/"Show Log Folder"/"Show Plugin Folder" context menu options are broken on some Linux hosts.
  Workaround: go find those folders yourself (see above), and the manual is over here.
• Some hosts do not paint the realtime visualization (graphs and knobs) for VST3. This affects mostly Linux hosts, but some Windows/Mac as well. CLAP should be OK everywhere, and even for VST3 it's not a big deal, just means you don't get realtime visual feedback.
  Maybe related: https://forums.steinberg.net/t/dataexchange-on-linux/917660/4.
  

Special Thanks

• thoth-amon
  For being an early adopter and finding all sorts of corner-case bugs.
• RustoMCSpit
  For being an early adopter and helping out with various things on the UI and theming side.
• Surge Synth Team
  For help with loads of stuff, from low-level technical details to CLAP support to microtuning and probably more.

Dependencies

• CLAP SDK: https://github.com/free-audio/clap
• JUCE: https://github.com/juce-framework/JUCE
• Xsimd: https://github.com/xtensor-stack/xsimd
• MTS-ESP: https://github.com/ODDSound/MTS-ESP
• Steinberg VST3 SDK: https://github.com/steinbergmedia/vst3sdk
• Readerwriterqueue: https://github.com/cameron314/readerwriterqueue

Credits

• Same (modified) Freeverb: https://github.com/sinshu/freeverb.
• Stole the color-morphing noise algo from here: https://sampo.kapsi.fi/PinkNoise/.
• Same soft clippers: https://dafx.de/paper-archive/2012/papers/dafx12_submission_45.pdf.
• Same DSF algorithm: https://www.verklagekasper.de/synths/dsfsynthesis/dsfsynthesis.html.
• Same state variable filter: https://www.cytomic.com/files/dsp/SvfLinearTrapOptimised2.pdf.
• Smooth noise: https://www.scratchapixel.com/lessons/procedural-generation-virtual-worlds/procedural-patterns-noise-part-1/creating-simple-1D-noise.html
• Stole the new osci algos from here: https://www.taletn.com/reaper/mono_synth/.
  You have to download the zip to get at the PolyBLEP source for all waveforms.
• Compressor:
  Basic algorithm stolen from ChunkWare's SimpleComp (among others here https://github.com/jonathonracz/GoatMix/tree/master/GoatMix/Source/External/SimpleComp) and
  added soft knee support based on this https://github.com/tu-studio/IEMPluginSuite/blob/master/resources/Compressor.h.

Demo Material

Short tracks

• Short 1 mp3 renoise
• Short 2 mp3 renoise
• Short 2 (builtin compressor) mp3 renoise
• Short 3 mp3 renoise
• Short 4 mp3 renoise
• Short 5 nicer kicks mp3 renoise

Full length tracks

• Full 1 (progressive trance) mp3 renoise

Feature demos

• Plucked strings mp3 reaper
• FM + distortion 1 mp3 reaper
• FM + distortion 2 mp3 reaper
• Bowed strings mp3 reaper video
• FM + lfo demo mp3 reaper video
• Plucked strings + echo mp3 reaper
• FM + echo + echo mod mp3 reaper
• Saw + echo + echo mod mp3 reaper
• Mod matrix demo mp3 reaper video
• Distortion (still love it) mp3 reaper video
• Osci to osci compressor (Nice kicks) mp3 reaper
• Plucked strings + per-voice echo mod mp3 reaper
• GUI Reacting to Bitwig per-voice-modulation demo video
• 3 oscillator (5/8/3 voices) unison + global unison mp3 renoise
• Per-voice echo applied to only one out of 2 osci's mp3 reaper
• Global unison with different per-voice settings for coarse pitch, voice lfo to voice filter, and echo mp3 reaper

Screenshots

Main

Matrix

Unison

Multi-Tap Delay

MSEG

Settings