space · field guide ·

pitch tuning, explained

one semitone moves one piano key. one cent moves a hundredth of that distance. neither is a fixed number of hertz.

space's public build log records coarse semitone and fine cents tuning as shipped on october 22. the engine's first diagnostic was a 440 hz tone. this guide connects those controls to frequencies you can recognize when checking a note.

where will this note land?

start from a reference, then move it. the result is calculated locally, not a measurement of the running engine.

440.00 hz

1.0000× reference

440 × 2^(0 / 12) = 440.00 hz

the relationship

frequency = reference × 2^((semitones + cents / 100) / 12)

twelve semitones double the frequency. going down twelve halves it. adding 100 cents has the same pitch effect as adding one semitone; use fine tuning for the smaller adjustment, rather than treating cents as hertz.

reference examples from a4, calculated
moveratioresult
−12 semitones0.5×220 hz
+1 semitone1.0595×466.16 hz
+12 semitones2×880 hz

use it when checking a sound

if an octave-up setting lands near 220 hz from a 440 hz reference, the direction is reversed. if a small cents change moves the note by a huge interval, check the cents-to-semitones conversion. compare the expected result here with a tuner or a rendered wav measurement.

this page does not play audio, measure cpu, or prove a browser voice works. space's public log distinguishes released offline diagnostics from the playable browser instrument and records listening issues separately.