Bitter Sweet
Key Features
- Single-knob transient control: Sweet reduces transients, Bitter magnifies them — instantly transforms the feel of any drum or percussion track
- Three Transient Integration modes (Fast, Medium, Slow) for matching processing speed to the source material
- MS matrix-based Operation Modes (Main, Center, Stereo) allow targeted processing of the mid or side channels independently
- Supports up to 16 channels I/O with 64-bit internal floating-point processing at up to 96 kHz sample rates
- True bypass with smooth transition, plus a Link-to-Output-Gain control for automatic unity-gain compensation
- Full Apple Silicon (M1/M2/M3) native support and AAX DSP compatibility for Pro Tools hardware acceleration
- No iLok or dongle required — activates via a free Flux account through the FluxCenter download app
Description
Bitter Sweet is Flux's acclaimed free transient designer — a single-knob processor used by hundreds of thousands of producers for shaping the attack and sustain of drums, percussion, and any dynamic audio source. Since its first release, it has earned a reputation that genuinely rivals many commercial transient processors.
Turning the central knob toward Sweet reduces transient amplitude — softening hits and pulling percussive instruments back in the mix. Rotating toward Bitter magnifies transients, adding snap, punch, and presence to kick drums, snares, and cymbals.
Bitter Sweet also includes a Transient Integration control with three processing modes (Fast, Medium, Slow) to tailor the detector response to the source material. An MS matrix-based Operation Mode selector lets you process the full stereo signal, isolate only the Mid channel for tightening kick and snare, or target only the Side channel for controlling panned hi-hats and overheads.
The plugin supports up to 16 channels of I/O, runs at sampling rates up to 96 kHz, and processes internally at 64-bit floating-point precision. It is fully Apple Silicon native with AAX DSP support — unusually capable for freeware — and requires only a free Flux account via their FluxCenter app, with no iLok or dongle needed.
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Frequently Asked Questions
Does Bitter Sweet support VST3 and AAX?
Yes. On macOS it is available in AAX, AAX DSP, AU, VST, and VST3 formats. On Windows it supports AAX, AAX DSP, VST, and VST3. AU is macOS-only. It also supports AAX Venue for live sound consoles — an unusual capability for a free plugin.
Is Bitter Sweet still maintained and compatible with modern DAWs?
Yes. Flux continues to actively distribute Bitter Sweet. As of 2024 it is confirmed compatible with Apple Silicon Macs (M1/M2/M3) and current versions of Pro Tools, Logic Pro, Ableton Live, and other major DAWs. It was highlighted in 2024 as unusually up-to-date for a long-running freeware plugin.
Do I need to create an account to download Bitter Sweet?
Yes. Bitter Sweet is distributed through Flux's FluxCenter app, which requires a free Flux account to access. There is no iLok or paid license — just a free sign-up on the Flux website before downloading and installing the plugin.
When should I use Center or Stereo mode instead of Main?
Center mode engages an internal MS encoder and processes only the Mid channel — effective for tightening snare and kick drum presence without affecting the stereo image. Stereo mode processes only the Side channel, which is useful for controlling panned hi-hats, overheads, and other rhythmic elements at the edges of the mix.
