Sympiano mark: a vibrating brass S over piano strings

SYMPIANO & Co.

The inside of a grand piano, as a reverb.

Sympathetic Resonance Works · est. 2026

Download Free for macOS Hear It First

One-click installer · AU · VST3 · Standalone · Apple Silicon & Intel · signed & notarized · genuinely free · or the .zip

What it is

230 strings, listening to your music.

Hold the sustain pedal of a grand piano and sing into it: every string that shares a frequency with your voice hums back. Sympiano is that instrument, as a plugin: a physical model of all 230 strings of a grand (or upright), each one a tuned resonator with real inharmonicity, coupled at the bridge, damped by felt, and picked up by a virtual piezo you can slide along the string.

It is not a convolution of a piano. It is the piano itself: strings, dampers, pedal and all, resonating with whatever you feed it.

The Sympiano interface: a viewport into a piano with copper bass strings, a gold plate strut, wooden dampers, and brass controls

The listening room

Hear the strings bloom.

Real instruments, played into the strings: pedal down, dampers up.

I. Acoustic pianoa piano, reverberating in a piano
II. Snare drumevery hit blooms across 230 strings
III. Cellobowed strings meet struck-string resonance
IV. A voice, inside the pianothe strings answer, listen for the tail

The mechanism

What the knobs are attached to.

MIDI dampers

Route MIDI at it and only the strings you hold resonate. The sustain pedal works, including half-pedalling, and the top octaves stay open, damper-free, exactly like the real instrument.

Scale-aware resonance

No MIDI? Choose a root and one of 21 scales, from Ionian to Altered to Bebop, and only in-key strings ring. A reverb that always lands in the key of your track.

A movable piezo

Slide the pickup along the strings: near the bridge for glassy close-mic bite, at the halfway point to hollow out every even partial. It is physics, not EQ.

Freeze

Lock the strings at zero loss and the current resonance hangs forever: an instant tuned pad. Feed it new audio while frozen, or let it stand.

Grand & upright

Two physically distinct instruments. String lengths, stiffness, decay and the overstrung bass crossing all change: the upright growls, the grand sings.

The standard kit

Pre-delay, ducking, wet low/high cut, unison detune from concert-fresh to saloon, stretch tuning, four temperaments, una corda, felt mute, stereo width.

Under the plate

For the technically curious.

Sympiano is not a convolution reverb and contains no samples or impulse responses. It is a real-time digital-waveguide physical model, the same family of techniques used to model instruments from first principles, solved live, every sample, for every string.

230 living strings

Each string is its own waveguide loop with Fletcher–Rossing inharmonicity fitted per register. Change the tuning and the physics follows: there is nothing pre-rendered to go stale.

The Weinreich aftersound

Unison strings are genuinely coupled at the bridge, so the famous two-stage piano decay and slow unison beating emerge from energy exchange. They are not chorus effects painted on top.

Practical or experimental

At low mix it is glue: a tuned, always-in-key sheen no algorithmic reverb produces. Pushed hard, with freeze, max coupling, saloon detune and a bridge-close pickup, it becomes a drone instrument, a resonant filter bank, a texture machine.

Light enough to spend freely

The whole instrument runs at roughly a tenth of one CPU core at 48 kHz, independent of buffer size down to 32 samples: fit for live use and for stacking across a session.

Physics all the way out

The pickup control is a real tap position on the string (its comb filtering falls out of the wave equation), half-pedalling morphs actual damper loss, and the top octaves ring free because real pianos have no dampers up there.

Engineered, then audited

Over a million automated assertions on tuning (±3 cents), decay times, stability and hostile-input handling, plus an independent security review, before version 1.0 shipped.

Particulars

Specifications.

FormatsAudio Unit (MIDI-controlled effect, macOS), VST3, Standalone app
Minimum systemmacOS 11.0 or later (Apple Silicon or Intel, universal) or Windows 10/11, 64-bit · any 64-bit VST3 host, or AU on macOS, or the included standalone app · ~40 MB disk, ~100 MB RAM · MIDI input optional
Engine230 digital-waveguide strings · 88 unison groups · bridge-coupled · ~10% of one core at 48 kHz (Apple M-series), ~20% at 96 kHz · buffer-size independent down to 32 samples · Eco mode ~4%
Sample rates44.1 / 48 / 96 / 192 kHz
PriceFree. No account, no email, no dongle.
PrivacyThe plugin makes one optional, anonymous version-check request per day to this site. It can be turned off in the plugin. Nothing else ever leaves your machine.
In LogicFind Sympiano under MIDI-controlled Effects on an instrument track; feed it audio via the side-chain picker. Full guide in the download.

macOS

Installer 1.0.3 (.pkg) Zip (manual install)

Windows

Installer 1.0.3 (.exe) Zip (manual install)

The Windows build is not yet code-signed, so SmartScreen may warn on first launch. Click “More info,” then “Run anyway.” VST3 and standalone, 64-bit.

Mirror on GitHub

The tuner's ledger

Release notes.

1.0.3Aug 2026 · Now plays on Windows, as VST3 and standalone. A one-click macOS installer joins the zip. Every knob answers on hover, and a new “?” opens the story of the instrument and a line to the maker.
1.0.2Aug 2026 · Dropdown menus now open inside the plugin window, which restores them in Audacity and other hosts with strict window management. The maker's full name on the nameplate.
1.0.1Aug 2026 · The binaries now report their true version number; 1.0.0 introduced itself as 0.1.0 and pestered everyone with a phantom update notice.
1.0.0Aug 2026 · First public release. 230 strings, tuned and delivered.