Calcophony

Every module free for 7 days. Tempo and metric modulation, tuplets, polyrhythms, harmonic series, tuning, spectral analysis, metronome, tuner. Then pay once.

Calcophony is a scientific calculator for composers and musicians. It handles the mathematical side of music composition, from tempo and metric modulation to tuning systems, just-intonation ratios, polyrhythms, spectral analysis, and spectrograms, plus a metronome and a chromatic, instrument-aware tuner.

TEMPO MODULATION CALCULATOR

Enter a starting tempo and see every note-value reinterpretation at a glance. A matrix shows the resulting BPM for each pivot, with near-integer results highlighted. Configurable tolerance, tuplet complexity, and target-BPM matching.

METRIC MODULATION PLANNER

Bridge distant tempos in multiple steps. Enter a start and target BPM and get chains of intermediate tempos with pivot note values at each transition. Compare alternative paths, see the deviation from target, and constrain by max steps, tuplet complexity, and tolerance.

RHYTHM & SUBDIVISION CALCULATOR

Work out complex rhythmic relationships, including tuplets and nested groupings. Get exact per-note durations in milliseconds, total duration, and equivalent note-value groupings.

POLYRHYTHM VISUALIZER

Audition polyrhythms: enter two or more pulse streams over a base tempo and see attack points and coincidences, with a distinct click timbre, mute, and solo per stream.

FREQUENCY & PITCH CONVERTER

Convert bidirectionally between Hz, pitch name, MIDI note number, and cents. Configurable reference pitch. Audition the current pitch from the app.

HARMONIC SERIES EXPLORER

Visualize and audition the overtone series from any fundamental. Partials are listed with frequency, nearest pitch, and cents. Toggle harmonic or subharmonic series, highlight interval and chord families, and play one or many at once.

INTERVAL & TUNING CALCULATOR

Analyze any interval entered by name, ratio, or cents. Get the simplest just-intonation ratio within a selectable prime limit (3, 5, 7, 11, 13, and higher), the nearest and second-nearest 12-TET intervals, cents deviation, decimal ratio, and beat frequency.

RATIO CALCULATOR

Stack just-intonation ratios with exact arithmetic. Enter intervals as fractions, then multiply, divide, and raise them to powers. Every result is a fully simplified fraction, shown both octave-reduced and in full register, with decimal and cents values. Stack twelve fifths to reveal the Pythagorean comma.

SPECTRAL CALCULATOR

Compute sum, difference, Tartini, and second-order combination tones for a set of input frequencies. Reinforced tones are highlighted, and implied fundamentals list bass notes whose harmonic series fits all your inputs.

SPECTROGRAM ANALYZER

Visualize the frequency content of any sound over time. Import an audio file or record from the microphone, then explore the spectrogram with pinch-to-zoom and pan. Tap any point to read the loudest partials there, audition them, and find the implied fundamental.

DURATION CALCULATOR

Generate a full table of note-value durations at any tempo, in milliseconds and MM:SS.mmm. An optional offset shifts every result for scoring and session work.

METRONOME

Presets for common and asymmetric meters (3/4, 5/8, 7/8, 12/8, and more), eleven sound sets (click, woodblock, rim, clave, hi-hat, cowbell, agogo, triangle, bongo, electronic, silent), custom accent patterns, subdivision clicks, tap tempo, count-in, and tempo ramping.

TUNER

Real-time pitch detection with built-in presets for guitar, bass, violin, viola, cello, double bass, ukulele, mandolin, and banjo, plus alternate tunings including Drop D, DADGAD, and Open G. Meter and strobe display modes, adjustable tolerance, selectable historical temperaments (Werckmeister III, Kirnberger III, Vallotti, Young I, quarter-comma meantone, and Pythagorean), reference A4 control, per-string reference tones, and semitone transposition.

Free tier includes Tempo Modulation, Frequency & Pitch, and the Metronome. A 7-day free trial unlocks every module. A single one-time purchase unlocks everything permanently, with no subscriptions.