Part of Vivaldi Studio · iPad & Mac

Vivaldi Keyboard

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.

Made for musicians, theory teachers, tuners, and historical-tuning nerds. We dare you to find this elsewhere.

Vivaldi Keyboard — steampunk wheels and 88-key piano

What it does

Five steampunk wheels, an 88-key piano, and the math underneath. That's the whole app — and it's enough.

22 Temperaments

Equal, Just Intonation, Meantone, Well Temperaments, Historical reconstructions, Pythagorean, World scales. Switch with a turn of the wheel.

21 Transposing Instruments

Saxes, clarinets, brass, strings, woodwinds — verified MIDI ranges and correct octave transposition. The keyboard dims keys outside your instrument's range.

Concert Pitch, for real

Play a written C on Alto Sax, hear the actual E♭ concert at the temperament's exact frequency. No mental math, no approximation.

Cent Deviations Panel

See the exact offset of every note from Equal Temperament. Open the ¢ tab and watch the math.

Variable Reference Note

For non-equal temperaments, choose which key is pure. Shift the wolf, find the sweet spots.

Custom SoundFont

FluidR3 GM is bundled (142 MB). Want your own piano? Import any .sf2 from Files.

All 22 Temperaments

Seven categories. Each comes with a description in the in-app guide — what it sounds like, where it came from, why it matters.

Regular

Equal (12-TET)

Just Intonation

5-limit7-limit

Meantone

1/4 comma1/3 comma1/5 comma1/6 comma2/7 comma

Well Temperament

Werckmeister IIIKirnberger IIIVallottiYoungNeidhardtBarnes

Historical

Bach / LehmanRameauKellner

Pythagorean

Pythagorean

World / Extended

19-TET31-TET53-TETArabic 24-TET

Transposing Instruments

Twenty-one instruments with verified MIDI ranges and correct octave transposition. Pick your instrument from the wheel, and the keyboard reshapes itself: keys outside your range fade 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.

C (Concert) Flute, Oboe, Trumpet C, Violin, Piano…
B♭ Clarinet B♭, Soprano Sax, Tenor Sax, Trumpet B♭, Flugelhorn
E♭ Clarinet E♭, Alto Sax, Baritone Sax
F French Horn, English Horn

…and more. Saxes, brass, strings, woodwinds — 21 in total.

Sounds

Five built-in timbres plus your own SoundFont. Multi-touch polyphony on iPad, click-to-play on Mac.

Piano

AVAudioUnitSampler with FluidR3 GM SoundFont (142 MB included)

Organ

Additive synthesis, baroque pipe-organ flavor

Sine

Pure sine wave — perfect for hearing temperament differences

Strings

Filtered sawtooth, sustained legato

Harpsichord

Plucked string synthesis

Custom SoundFont

Import any .sf2 file from Files. Your sample, your sound.

Reference Frequency

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.

A4 range
415 Hz 440 Hz 466 Hz

How it works

Five wheels above, an 88-key piano below. That's the whole interface.

1

Transpose

Pick your instrument. The keyboard adjusts range and concert pitch.

2

Temperament

Choose a category and a sub-temperament. Twenty-two options.

3

Reference

For non-equal temperaments, set which key is pure.

4

Sound

Piano, organ, sine, strings, harpsichord, or your own .sf2.

5

Play

88 keys. Multi-touch on iPad, click on Mac. Pinch to zoom, two-finger drag to scroll.

Frequency calculation

MIDI note touched
+ concertPitchOffset (from selected instrument)
= concert MIDI note

baseFreq = referenceFreq × 2^((midiConcert − 69) / 12)
+ cent offset from temperament
= final frequency

A glimpse

Vivaldi Keyboard view 1
Hold the side button, drag to scroll the keyboard.

Steampunk wheels and an 88-key piano. Landscape, always.

One purchase. iPad and Mac.

Universal Purchase: buy once, play on iPad and Mac. No subscription, no telemetry, no account.

€1.99 — coming soon to the App Store.

Support & Contact