BandMatrix

Released — Version 2.9.0.

Free 6-Band Sidechain Dynamics Plug-in

BandMatrix is a free 6-band sidechain dynamics plug-in with compression, expansion, flexible key routing, Tone Shaper mode, and Inverse sidechain mode. Each band can listen to the internal signal, external sidechain input, or another band, so you can create targeted ducking and inter-band control without compressing the whole mix.

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macOS: AU / VST3 for macOS 11 or later • Windows: VST3

Download v2.9.0 (PKG) Download Windows VST3 (ZIP)

The latest release is v2.9.0, with improved compressor release behavior and cleaner burst-boundary handling.

What it does

Split the signal into multiple bands and apply independent compression per band.
Per band, choose a key source: Internal, External sidechain, Mix, or Other band.
Create precise ducking (e.g., kick → bass low band) and inter-band control (e.g., harsh band → tame presence) without affecting the entire spectrum.
Version 2.9.0 improves compressor release behavior and reduces burst-boundary artifacts while preserving the static curve and transient pass-through.
Tone Shaper mode adds a more flexible way to shape spectral balance inside the band matrix workflow.
The window is now resizable for easier editing on different screen sizes.

BandMatrix UI screenshot — Screenshot: band routing, key selection, and per-band gain reduction.

Release history

v2.9.0 — Compressor behavior update.

Current release. Improves compressor release behavior and burst-boundary handling while preserving the static transfer curve and transient pass-through.

v2.6.0 — Tone Shaper Mix fix.

Fixed Mix control behavior in Tone Shaper mode.

Typical use cases

Kick / Bass

Duck only the bass low band from the kick, keeping mids and highs stable and punchy.

Vocals / Music

Make space for vocals by gently ducking specific instrument bands using internal or external keys.

Sound design

Create inter-band dynamics (one band driving another) for movement, emphasis, and controlled aggression.

Requirements

macOS 11 or later.
A plug-in host that supports AU or VST3.
Installer: BandMatrix_2.9.0.pkg

Note: The installer includes AU / VST3 builds that target macOS 11 or later.

Install

Download the latest BandMatrix_2.9.0.pkg from this page.
Run the installer (it installs AU / VST3 to the standard macOS plug-in locations).
Launch your host and rescan plug-ins if needed.

Support

Email: kjdevapphelp@gmail.com

Please include: OS version, host app version, and a short description (or screenshot) of the issue.