Audiomodern has released Soundbox 1.3, a free update that finally delivers what the plugin promised on its box two years ago: full MPE support. Per-note pitch bend, pressure and timbre now behave the way an MPE controller expects, across macOS, Windows, Linux and iOS. The update landed on 9 September 2026 and is free for every existing user.

It is worth being honest about the timeline, because the developer effectively has been. When Soundbox launched in late 2024, it was marketed as an MPE sampler. That was true only in a narrow sense — the plugin accepted MPE data, but the implementation was partial enough that anyone playing a Seaboard, LinnStrument or Osmose into it hit walls quickly. Version 1.3 replaces that half-measure with a proper implementation.

Why a Sampler Getting MPE Right Matters

Synth plugins have had a comparatively easy time adopting MPE. An oscillator's pitch is a number; bending it per voice is a modest architectural change. Samplers are harder. Per-note pitch bend on a multi-sampled instrument means resampling or repitching individual voices in real time while keeping formants, loop points and round-robin logic intact. Per-note timbre means the filter, and often the layer crossfade, has to become voice-local rather than global.

That is why the list of samplers with credible MPE support stays short, and why a free update on a plugin that anyone can download is more significant than the version number suggests. Soundbox is not a boutique curiosity — it is Audiomodern's answer to Kontakt, positioned deliberately at the cheap end.

The Soundbox Model, Briefly

The plugin itself is a free download. The playback engine is fully unlocked out of the box, so you can load and perform any Soundbox instrument, including the many free community libraries, without paying anything. What you cannot do without a licence is build instruments: the sample mapping and editing backend unlocks when you buy any official Audiomodern library, which start around €29.

That structure has produced something unusual — a genuine community of sound designers publishing custom .sbpack instruments without fees or revenue splits. For MPE players, that community is now the interesting part. Every existing Soundbox library becomes a candidate for expressive playing, and library authors can start designing patches with per-note pressure and slide in mind rather than treating them as an afterthought.

Under the hood, each Soundbox patch holds up to four sample instruments, each with its own ADSR, glide, transpose and a four-slot multi-effects chain (reverb, delay, EQ, filter, distortion, chorus, phaser, lo-fi, compressor, limiter, noise). Four assignable multi-wave LFOs, a per-layer arpeggiator with parameter step sequencing, and a vector pad for mixing the four layers round it out. Feed per-note timbre into a layer filter, and the vector engine into a slower gesture, and you have a reasonably deep expressive instrument.

The ConvertWithMoss Angle

The second half of the 1.3 release is easy to overlook but genuinely useful: the open-source ConvertWithMoss utility now supports Soundbox for both read and write.

In practice, that means multi-sample formats can be moved into and out of the Soundbox format without manual remapping. A DecentSampler patch, an SFZ instrument, a Kontakt-adjacent export — all become candidates for conversion into an .sbpack. If you have a shelf of sampled instruments you have never been able to play expressively, this is the path: convert to Soundbox, then let the new MPE engine handle the per-note data.

It is not magic. A library sampled with three velocity layers and no round-robins will still sound like a library sampled with three velocity layers. Continuous pressure mapped to a volume envelope on static samples produces swells, not the timbral change a real instrument makes when you push into a note. The realism ceiling is set by the source material, not the MPE implementation. But the difference between "no per-note control" and "per-note control over a static sample" is still large, particularly when you route timbre to filter and add a resonant layer underneath.

Availability

Soundbox 1.3 is available now as a free update on macOS, Windows, Linux and iOS, running as VST3, AU, AAX and AUv3. The plugin is a free download from Audiomodern; the sample editor unlocks with the purchase of any official library, and the free community expansions are listed on the expansions page.

If you own an MPE controller and have been ignoring Soundbox because its expression support was unreliable, this is the update that makes it worth a second look.