Calcophony
A scientific calculator for composers.
Tempo ratios, tuplet subdivisions, overtone frequencies, metric modulation paths: the kind of things you end up scribbling on manuscript margins or punching into a spreadsheet. Calcophony puts all of it in one place, with exact results you can trust.
Built for iOS and Android
Modules
Tempo Modulation Free
All tempo relationships from a source BPM. Explore all possible tempo modulations from a given starting point in a comprehensive matrix view, with tuplet complexity controls and configurable precision.
Metric Modulation
Plan multi-step modulations between distant tempos. Discover ordered chains of intermediate tempos with pivot note values, final deviation, and transition duration.
Rhythm & Subdivision
Work out complex rhythmic relationships. Get exact durations, click-track pulses, and equivalent groupings for nested tuplets and polyrhythms.
Frequency & Pitch Free
Bidirectional Hz, pitch name, cents, and MIDI conversion. Includes exact cents deviation and customizable reference pitch (e.g., A4 = 440 Hz).
Duration Calculator
Generate a full table of note-value durations at any tempo, with milliseconds, MM:SS.mmm elapsed-time output, and optional time offset.
Metronome Free
Create metronomes in any time signature with customizable sound sets, accent patterns, tempo ramps, and asymmetric meter support.
Polyrhythm Visualizer
Visualize composite rhythms with an interactive circular display. Configure up to 8 independent streams, find coincidence points, and audition the composite pattern with playback controls.
Harmonic Series
Visualize and audition the overtone series. Compare exact Hz to nearest 12-TET pitch with cents deviation, and play back individual partials.
Interval & Tuning
Convert intervals between ratios and cents, find the simplest just-intonation approximation within configurable error and prime-limit bounds, and see the distance to the two nearest 12-TET semitones with beat frequencies.
Spectral Calculator
Compute combination tones (sum, difference, Tartini, and second-order products) for any set of input frequencies. Identify which results reinforce existing partials and audition each tone directly.
Tuner
High-precision chromatic and instrument-aware pitch detection with strobe display. Supports built-in instrument tunings, historical temperaments, and reference tone playback.
Under the Hood
True Strobe Simulation
The strobe tuner is a real-time strobe disc simulation rendered by a native GPU module, not a cosmetic overlay on a traditional pitch detection algorithm. The disc rotation responds directly to measured phase, the same way a mechanical strobe tuner does.
Exact Arithmetic
Musical ratios are computed with true fractional arithmetic: no rounding errors, no approximations. Results stay mathematically exact until final display.
All On-Device
Every calculation runs locally. No account, no server round-trips, no telemetry required. Works offline.
Pricing
Free
$0
- Tempo Modulation
- Frequency & Pitch
- Metronome
- 7-day free trial of all modules
Pro
$9.99 one-time
- All modules unlocked
- Future modules included
- Try free for 7 days
- No subscription
Schools & institutions: get in touch about classroom and multi-device deployments, and we'll find the right option for you. Contact us for details.