FatSat

An analog-style saturation plug-in by fatbird Studios.

FatSat puts two distinct saturation characters under a single Drive control. Below 75 the signal is inflated rather than clipped — density and body increase while peaks stay where they are. At 75 the character breaks deliberately: from there upward the plug-in hard-clips and injects controlled odd-harmonic content, getting more aggressive as Drive approaches 100.

• Format: VST3
• Platforms: macOS 10.13+ (Universal Binary: Intel + Apple Silicon), Windows 10/11 (64-bit)
• Channels: mono / stereo

Controls

Control	Range	Description
Drive	0 – 100	Saturation character. Deliberate break in behaviour at 75.
Input Gain	−24 – +24 dB	Pre-saturation stage. Drives the saturator harder without raising the output peak.
Output Gain	−24 – +24 dB	Post-saturation level — the true peak control.
Blend	0 – 100	Wet/dry mix for parallel-style processing.
Bypass	on / off	Removes all processing from the signal path.
FatSat logo	1x / 4x	Oversampling. 4x reduces aliasing from the nonlinear stages.

Installation

macOS — run the installer. It places FatSat.vst3 in /Library/Audio/Plug-Ins/VST3/.

Windows — run the installer, or copy FatSat.vst3 from the zip into C:\Program Files\Common Files\VST3\.

Restart your DAW and rescan plug-ins afterwards.

Licence

FatSat is free software, licensed under the GNU Affero General Public License v3 (AGPLv3). See LICENSE for the full text.

FatSat is built on the JUCE Framework, which is dual-licensed under the AGPLv3 and a commercial licence. FatSat uses JUCE under the AGPLv3, so FatSat is distributed under the same terms. Third-party components and their licences are listed in THIRD-PARTY-NOTICES.txt.

The complete corresponding source for every released binary lives in this repository.

Brand assets

The AGPLv3 covers the source code. It does not cover the FatSat and fatbird Studios names, the logo, or the interface artwork under FatSat/Source/Assets/ — those are brand assets and remain the property of fatbird Studios, as permitted by AGPLv3 section 7(e).

You are free to build, modify and redistribute FatSat under the AGPLv3, but a redistributed build must not carry the FatSat or fatbird Studios branding and must not reuse the interface artwork. Replace the assets and rename the product. See THIRD-PARTY-NOTICES.txt for the full statement.

Building from source

Requirements:

• JUCE 8.x
• macOS: Xcode with command line tools
• Windows: Visual Studio 2022 with the "Desktop development with C++" workload

The Xcode/Visual Studio projects and JuceLibraryCode/ are generated by Projucer and are not checked in. Generate them first:

Projucer --resave FatSat/FatSat.jucer

Then build. On macOS, package_mac.sh performs a full release run — Universal Binary build, Developer ID signing, notarization and installer packaging:

./package_mac.sh

Use --no-notarize for a local build that skips the Apple notary service.

Credits

Interface artwork by @svedrif.jpeg.

VST is a trademark of Steinberg Media Technologies GmbH.