FM synthesis and MPE have always been a slightly awkward pair. FM can produce some of the most alive, articulate timbres in synthesis, but classic FM instruments were designed around velocity and maybe a mod wheel. Audio Damage is taking another run at that combination with Sandbender, a new four-operator FM synth with wavefolding, a modeled low-pass gate and, importantly for this audience, full MPE support.
The synth was announced on 11 November 2026 and is available now for $99, according to Synthtopia's launch coverage.
What Sandbender is
At its core, Sandbender is a four-operator FM engine. It ships with ten factory algorithms, and it also has an algorithm designer for building your own operator routings. Each operator can be tuned in three ways: by harmonic ratio, by free ratio, or at a fixed frequency. That last option matters for anyone who likes metallic, inharmonic or percussive tones that do not track the keyboard.
Audio Damage then layers some decidedly non-traditional shaping on top of the FM core:
- A per-operator waveshaper, so each operator can be bent before it modulates or is heard.
- A wavefolder with symmetric, asymmetric and soft-clip modes.
- A sub oscillator and six noise types.
- Eleven filter types.
- A modeled low-pass gate that can replace the usual VCA stage.
Modulation includes two ADSRs and two LFOs per voice, a 16-step sequencer, drag-and-drop modulation assignment, and four macros. Six built-in effects and more than 260 presets round out the package.
The MPE angle
The headline for expressive players is simple: the press materials describe "Full MPE support", alongside MTS-ESP microtuning. Sandbender runs up to eight voices and offers polyphonic, monophonic and retriggered-monophonic modes.
Why does this combination interest MPE players in particular? A few reasons stand out.
FM index is a natural pressure target. In FM, the modulation amount controls brightness and harmonic density. Map per-note pressure to operator levels and each finger can push its own note from a soft sine toward a bright, buzzy spectrum. That is a far more organic gesture than sweeping a global filter.
Wavefolding responds well to continuous control. Folding amount is another parameter that rewards small, smooth changes. With slide (CC74) on the fold depth, you can make individual notes in a chord grow edgier without touching the others.
A low-pass gate loves velocity and lift. Low-pass gates couple brightness and loudness, which is why they sound so plucky and acoustic. On an MPE controller with strike velocity and release velocity, this kind of gate can make FM tones feel struck, bowed or plucked depending on how you play.
Microtuning plus per-note pitch. MTS-ESP support means Sandbender can follow a shared tuning source across your session. Combined with per-note pitch bend, that opens the door to expressive slides within a non-12-TET scale. If you are new to this, our MPE and MTS-ESP microtuning guide covers the basics.
Eight voices: plan around it
Eight voices is enough for most MPE playing, but it is worth keeping in mind. MPE gives each sounding note its own MIDI channel, and with long release tails or a sustain pedal, eight voices can fill up quickly during dense pad work. For leads, basses, plucks and chordal comping, it should feel comfortable. If you play big sustained clusters, consider shorter releases or the monophonic modes for lead lines.
Before you buy, it is still good practice to check how the MPE implementation behaves in your setup: the default pitch-bend range, whether pressure and slide are pre-mapped in the factory presets, and how the synth handles voice stealing. Our MPE support buyer's checklist walks through those questions.
Platforms and availability
Sandbender runs on macOS, Windows, Linux and iOS. Linux support is still relatively rare among commercial synths, and the iOS version is good news for anyone pairing an iPad with a compact MPE controller.
Audio Damage has a solid history with expressive instruments, including earlier MPE-aware releases like Continua. Sandbender looks like a focused, affordable way to bring FM into an MPE rig without wrestling with a vintage-style interface.
You can find details, audio demos and purchase options on the official Sandbender page.