Part of Vivaldi Studio · the intonation bench
An 88-key piano with twenty-two historical temperaments and twenty-one transposing instruments. Hear what your alto sax actually plays. Tune your harpsichord in 1/4-comma meantone. Compare Equal Temperament against Pythagorean, in cents, in real time.
Touch the screen, plug in a Bluetooth keyboard, hit Space for Sustain on Mac. Made for musicians, theory teachers, tuners, and historical-tuning nerds. We dare you to find this elsewhere.
More than a keyboard: an 88-key instrument built around real tuning and transposition. Historical temperaments, transposing instruments, concert pitch, your own SoundFonts — here's what's inside.
Equal, Just Intonation, Meantone, Well Temperaments, Historical reconstructions, Pythagorean, World scales. Switch with a turn of the wheel.
Saxes, clarinets, brass, strings, woodwinds — verified MIDI ranges and correct octave transposition. The keyboard dims keys outside your instrument's range.
Play a written C on Alto Sax, hear the actual E♭ concert at the temperament's exact frequency. No mental math, no approximation.
See the exact offset of every note from Equal Temperament. Open the ¢ tab and watch the math.
For non-equal temperaments, choose which key is pure. Shift the wolf, find the sweet spots.
Import any .sf2 from Files or iCloud. The app parses every preset inside — melodic banks, drum kits, dozens of instruments — and lets you pick from a scrollable preset list. Swap presets live while you play.
Plug in a Bluetooth keyboard on iPad, or use the Mac keyboard directly. S D F G H J K L for white notes, E R Y U I for black notes. Shift octave live with [ and ]. Full C0–C8 range.
Sustain, Sostenuto, Soft — turn on the ones you use, switch off the rest in settings. Touch or drag on iPad, or Space / X / C on Mac. The Soft pedal affects only the notes played while it is held, exactly like a real piano.
Siri, an incoming call, a system alert — the audio engine pauses cleanly and resumes when the interruption ends. No more silent app after a phone call.
Seven categories. Each comes with a description in the in-app guide — what it sounds like, where it came from, why it matters.
Twenty-one instruments with verified MIDI ranges and correct octave transposition. Pick your instrument from the wheel and the keyboard reshapes itself: keys outside the playable range dim out, frequencies shift to match your concert pitch.
Play a written C on alto sax → you hear the actual concert E♭, at the exact frequency of the selected temperament. No conversion in your head. Ever.
Twenty-one transposing instruments plus Concert pitch. Real ranges, real transposition.
Five built-in instruments from a bundled 142 MB FluidR3 GM SoundFont, plus any .sf2 you import. Multi-touch polyphony on iPad, click-to-play on Mac.
Acoustic grand — warm, full-bodied, the default starting point.
Church organ — deep, sustained; pairs well with well-temperaments.
GM flute — clean, single-voice; perfect for hearing temperament differences.
String ensemble — sustained legato, great for hearing beating intervals.
Percussive attack, brittle overtones; made for historical temperaments.
Need more? The SoundFont + Bank Selection pillar above covers custom .sf2 imports with live preset switching.
Configurable from 415 Hz (baroque pitch) to 466 Hz (high orchestral). Default is the modern A = 440 Hz.
Frequency updates instantly while you play. Pair it with a meantone temperament and suddenly you're rehearsing on a real harpsichord — without owning one.
Switch it on from Settings → Debug → Show frequency overlay and a small panel appears in the top-right corner. It shows the exact frequency in Hertz of the last note you played, plus the current zoom of the keyboard.
Useful to verify that A4 is 437.39 Hz in 1/4-comma meantone with Root = C, 440.00 Hz in equal temperament, or whatever the active combination produces. The number updates live as you play.
A4 in 1/4 comma meantone, Root = C
Three wheels above, an 88-key piano below, a reference-pitch slider alongside. That's the whole interface.
Turn the Transpose wheel, then pick your exact instrument from the rail that appears.
Keys outside the instrument's playable range dim out. You still see them, but you know.
Choose a category on the Temperament wheel. For non-equal tunings, a Root Note rail appears to pick which key is pure.
Piano, organ, flute, strings, harpsichord — or any .sf2 with live preset switching.
88 keys. Multi-touch on iPad, click on Mac. Hold the left-edge circle: one finger drags to scroll, two fingers drag up or down to zoom.
MIDI note touched + concertPitchOffset (from selected instrument) = concert MIDI note baseFreq = referenceFreq × 2^((midiConcert − 69) / 12) + cent offset from temperament = final frequency
A single hold circle on the left edge. One finger drags to scroll the 88 keys. Two fingers drag vertically to zoom in and out. No menus, no toolbars.
Landscape only.
Multi-touch on the screen is great. Plugging in a real keyboard is greater. On Mac, the keyboard is the instrument.
Pair any Bluetooth keyboard to your iPad, or use the Mac keyboard directly. The QWERTY row plays one full octave; the row above it gives you the black keys.
Choose the starting octave in Settings → Physical keyboard.
Touch and drag on iPad — drag forward to lock on or off with one natural gesture. On Mac the keyboard shortcuts cover everything.
Visual feedback — three small lamps on the right rail show the live state of each pedal:
The Soft pedal affects only the notes you play while it is engaged. Notes already ringing (held by Sustain or Sostenuto) keep their original volume — exactly like a real piano.
Three short walk-throughs — the temperament in action, the SoundFont import, and the pedals.
Tutorial 1
An E major triad in 1/4-comma meantone — pure, beatless thirds. Watch the frequency tip in the top-right corner.
Tutorial 2
Switch from a built-in preset to a custom .sf2 — same keys, different instrument.
Tutorial 3
A walk-through of the three pedals and the Mac shortcuts.